<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:7263b5f8-0719-4f3f-b8c4-88a450da33d1,g:d4487cf6-2268-4cad-b5c1-d281398ed695-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.veracyte.com/role/CondensedConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="vcyt-20220630.xsd#CondensedConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/CondensedConsolidatedStatementsofOperations" xlink:type="extended" id="i5cd65bfa2a774af2af56cc1f65452745_CondensedConsolidatedStatementsofOperations">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_5d023245-206a-48ae-850a-70469d4b681c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_RevenuesAbstract_5d023245-206a-48ae-850a-70469d4b681c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_1340e84d-69fd-406e-8328-70d2bb97c4be" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5d023245-206a-48ae-850a-70469d4b681c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_1340e84d-69fd-406e-8328-70d2bb97c4be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_f1d19d76-f910-402d-9867-6efe1a4a368d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_CostOfRevenue_f1d19d76-f910-402d-9867-6efe1a4a368d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_11697250-af24-496a-a996-88dbd8aa9266" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_11697250-af24-496a-a996-88dbd8aa9266" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_16a40d36-e15f-4ccb-ad73-3599a669d79a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_SellingAndMarketingExpense_16a40d36-e15f-4ccb-ad73-3599a669d79a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_18e77d55-e3f3-46b4-9d24-a3ec4c14e122" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_18e77d55-e3f3-46b4-9d24-a3ec4c14e122" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_20871e22-e1c8-44a1-920d-7c6ffdef7e5b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_20871e22-e1c8-44a1-920d-7c6ffdef7e5b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_3392f23f-decd-46f6-98dc-9da03dd1a997" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_164af530-566f-413e-8fdb-4dc325323732" xlink:to="loc_us-gaap_CostsAndExpenses_3392f23f-decd-46f6-98dc-9da03dd1a997" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_f50ea0d4-5f3f-41cd-a449-e039b7dbdd29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_OperatingIncomeLoss_f50ea0d4-5f3f-41cd-a449-e039b7dbdd29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_e7a63b88-5779-413c-b7d5-67033cb078d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_e7a63b88-5779-413c-b7d5-67033cb078d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_343c1a29-ee47-4d22-aea5-5f831637a692" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_343c1a29-ee47-4d22-aea5-5f831637a692" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_13123ed0-fbf2-41c3-b57b-a947b303c6b3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_13123ed0-fbf2-41c3-b57b-a947b303c6b3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_979d77bc-b7d7-40a4-a6b9-44484da0b3ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_NetIncomeLoss_979d77bc-b7d7-40a4-a6b9-44484da0b3ef" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_c361183a-4782-4304-980c-2cf62adda43c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_EarningsPerShareBasic_c361183a-4782-4304-980c-2cf62adda43c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_a7e203e4-7d2e-44db-bf63-690b0ab4c14f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_EarningsPerShareDiluted_a7e203e4-7d2e-44db-bf63-690b0ab4c14f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_91e40055-5bbd-423e-b4b4-59d220a9868b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_91e40055-5bbd-423e-b4b4-59d220a9868b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6062e915-aad6-4a32-8550-f40fbeb10b1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6062e915-aad6-4a32-8550-f40fbeb10b1d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_cf8c51a2-3e93-435b-8940-6210391bc7f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_de624728-c8fe-4b5b-870a-c70e0aa0fb5e" xlink:to="loc_us-gaap_StatementTable_cf8c51a2-3e93-435b-8940-6210391bc7f2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_cf8c51a2-3e93-435b-8940-6210391bc7f2" xlink:to="loc_srt_ProductOrServiceAxis_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c" xlink:to="loc_srt_ProductsAndServicesDomain_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_bc203ea1-414b-4b77-af67-605ec54d3cc9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_13d5501d-06aa-4ca2-81ee-3b0c8f366f7c" xlink:to="loc_srt_ProductsAndServicesDomain_bc203ea1-414b-4b77-af67-605ec54d3cc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_TestingMember_b6e92c6e-8a02-40a0-87f9-5f2754550152" xlink:href="vcyt-20220630.xsd#vcyt_TestingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc203ea1-414b-4b77-af67-605ec54d3cc9" xlink:to="loc_vcyt_TestingMember_b6e92c6e-8a02-40a0-87f9-5f2754550152" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_a2ea1f67-b9cc-4ed2-b688-32a1b3d2d41a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc203ea1-414b-4b77-af67-605ec54d3cc9" xlink:to="loc_us-gaap_ProductMember_a2ea1f67-b9cc-4ed2-b688-32a1b3d2d41a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BiopharmaceuticalAndOtherMember_6ce0877d-fbdb-4d4d-af32-eb3d0b00df1b" xlink:href="vcyt-20220630.xsd#vcyt_BiopharmaceuticalAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc203ea1-414b-4b77-af67-605ec54d3cc9" xlink:to="loc_vcyt_BiopharmaceuticalAndOtherMember_6ce0877d-fbdb-4d4d-af32-eb3d0b00df1b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/CondensedConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="vcyt-20220630.xsd#CondensedConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/CondensedConsolidatedStatementsofStockholdersEquity" xlink:type="extended" id="i756cb475558445859d3eb4cdf7a4e468_CondensedConsolidatedStatementsofStockholdersEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_be64cf37-d807-4109-96da-4a3b6d6afea5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_be64cf37-d807-4109-96da-4a3b6d6afea5" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_421856ef-ba9d-4e4b-8d9d-bef765adee7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_SharesOutstanding_421856ef-ba9d-4e4b-8d9d-bef765adee7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c83dd699-a5c6-4ef0-88df-7f61cca2741a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_StockholdersEquity_c83dd699-a5c6-4ef0-88df-7f61cca2741a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_StockIssuedAndSoldDuringPeriodSharesInPrivatePlacement_6ef295f6-0ed7-45b7-99ec-a8bf6f47af34" xlink:href="vcyt-20220630.xsd#vcyt_StockIssuedAndSoldDuringPeriodSharesInPrivatePlacement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_StockIssuedAndSoldDuringPeriodSharesInPrivatePlacement_6ef295f6-0ed7-45b7-99ec-a8bf6f47af34" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_StockIssuedAndSoldDuringPeriodValueInPrivatePlacement_a3443936-e3f1-4915-ae7f-147884808f78" xlink:href="vcyt-20220630.xsd#vcyt_StockIssuedAndSoldDuringPeriodValueInPrivatePlacement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_StockIssuedAndSoldDuringPeriodValueInPrivatePlacement_a3443936-e3f1-4915-ae7f-147884808f78" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndNonOptionEquityInstrumentsExercisesInPeriod_dd0e54cd-55c4-4e56-b1aa-c9fee7369ec9" xlink:href="vcyt-20220630.xsd#vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndNonOptionEquityInstrumentsExercisesInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndNonOptionEquityInstrumentsExercisesInPeriod_dd0e54cd-55c4-4e56-b1aa-c9fee7369ec9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardValueOptionsAndNonOptionEquityInstrumentsExercisesInPeriod_984648f1-5d68-48b6-9fcd-01a9756bc06b" xlink:href="vcyt-20220630.xsd#vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardValueOptionsAndNonOptionEquityInstrumentsExercisesInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_ShareBasedCompensationArrangementByShareBasedPaymentAwardValueOptionsAndNonOptionEquityInstrumentsExercisesInPeriod_984648f1-5d68-48b6-9fcd-01a9756bc06b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_a26affde-ed71-4766-b057-c0ceeb70bd7c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_a26affde-ed71-4766-b057-c0ceeb70bd7c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_7ad80359-868c-413f-b647-e08a6ef3ad27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_7ad80359-868c-413f-b647-e08a6ef3ad27" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_6de17e36-0140-47ec-bc1e-960ab7fe3bf6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_6de17e36-0140-47ec-bc1e-960ab7fe3bf6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployee_20e4328c-e135-419a-845d-a1ae100d58fb" xlink:href="vcyt-20220630.xsd#vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployee_20e4328c-e135-419a-845d-a1ae100d58fb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationNonEmployee_18e20a8c-b54a-4110-ad2f-eb82ad8ef7fe" xlink:href="vcyt-20220630.xsd#vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationNonEmployee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationNonEmployee_18e20a8c-b54a-4110-ad2f-eb82ad8ef7fe" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationESPP_c33f9d55-81cd-45a1-8175-29de0f218ac6" xlink:href="vcyt-20220630.xsd#vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationESPP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_vcyt_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationESPP_c33f9d55-81cd-45a1-8175-29de0f218ac6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_f7d14cf1-1e26-4973-a586-97e987964d75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_NetIncomeLoss_f7d14cf1-1e26-4973-a586-97e987964d75" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_ad0b8ec0-47ea-4d2a-862d-16de7be2f283" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_27a70804-0c21-4b81-9b9c-6e2f5c4c9a3b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_ad0b8ec0-47ea-4d2a-862d-16de7be2f283" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_b6b53c7e-7793-446a-bced-25007f85bced" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_8f4928df-a2c1-4877-8631-1a722cb1617d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a34a8ecb-60ed-4437-8fca-fb2311e05f64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_be64cf37-d807-4109-96da-4a3b6d6afea5" xlink:to="loc_us-gaap_StatementTable_a34a8ecb-60ed-4437-8fca-fb2311e05f64" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_32205b3d-a854-4608-938b-e6f2868f8f33" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a34a8ecb-60ed-4437-8fca-fb2311e05f64" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_32205b3d-a854-4608-938b-e6f2868f8f33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_32205b3d-a854-4608-938b-e6f2868f8f33_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_32205b3d-a854-4608-938b-e6f2868f8f33" xlink:to="loc_us-gaap_EquityComponentDomain_32205b3d-a854-4608-938b-e6f2868f8f33_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_32205b3d-a854-4608-938b-e6f2868f8f33" xlink:to="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_a8fd0624-de92-46aa-85f6-78a281e28197" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:to="loc_us-gaap_CommonStockMember_a8fd0624-de92-46aa-85f6-78a281e28197" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_fe874689-abb9-4000-a002-469c7d3258a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_fe874689-abb9-4000-a002-469c7d3258a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_abbce533-90f3-4aef-81b7-539ff66d701c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:to="loc_us-gaap_RetainedEarningsMember_abbce533-90f3-4aef-81b7-539ff66d701c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2e804501-a7d5-425a-915e-a5790f176015" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5317656c-e4af-4242-9b4a-2bde2c10b804" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2e804501-a7d5-425a-915e-a5790f176015" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" id="i745d65bdda1d4919a0f2f91a0fba606b_OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_845632d4-8a67-4d47-b5b7-77eaa755552e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_NumberOfOperatingSegments_845632d4-8a67-4d47-b5b7-77eaa755552e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_f1539706-f8a9-41b5-9c53-b53abf97a770" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_f1539706-f8a9-41b5-9c53-b53abf97a770" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_d49001b6-0f23-4602-b9eb-95a86367f6d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_d49001b6-0f23-4602-b9eb-95a86367f6d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_b571ca47-d811-477a-ba2d-2a6116dc724b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_b571ca47-d811-477a-ba2d-2a6116dc724b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_53590f60-a448-422b-8060-e13c015dd3aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_53590f60-a448-422b-8060-e13c015dd3aa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_ec21b532-4eeb-4fd6-b4c2-fd2412a0d4d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_ec21b532-4eeb-4fd6-b4c2-fd2412a0d4d3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_82615ddd-a4c4-4498-b10d-4dca215ffbe5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_82615ddd-a4c4-4498-b10d-4dca215ffbe5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_54c2e9f2-8585-49fa-9535-9a776f9ef698" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_ContractWithCustomerLiability_54c2e9f2-8585-49fa-9535-9a776f9ef698" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_b7181598-2c09-4321-ba62-5e322249d0f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_b7181598-2c09-4321-ba62-5e322249d0f2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanTypeExtensibleList_e5f89963-ba22-48fd-9a24-e59de50a6329" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanTypeExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligation_b7181598-2c09-4321-ba62-5e322249d0f2" xlink:to="loc_us-gaap_DefinedBenefitPlanTypeExtensibleList_e5f89963-ba22-48fd-9a24-e59de50a6329" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_cb996464-c723-4535-8f6c-9b3f96537c06" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAxis_3f896c08-44b1-4ad5-88e8-8d7292a7845f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:to="loc_srt_RestatementAxis_3f896c08-44b1-4ad5-88e8-8d7292a7845f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_3f896c08-44b1-4ad5-88e8-8d7292a7845f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RestatementAxis_3f896c08-44b1-4ad5-88e8-8d7292a7845f" xlink:to="loc_srt_RestatementDomain_3f896c08-44b1-4ad5-88e8-8d7292a7845f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_f85b5c6e-7ff8-4bc9-b466-08cc526c329a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RestatementAxis_3f896c08-44b1-4ad5-88e8-8d7292a7845f" xlink:to="loc_srt_RestatementDomain_f85b5c6e-7ff8-4bc9-b466-08cc526c329a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember_5b74450f-33a8-43dd-95e9-27ebf9c876ef" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RevisionOfPriorPeriodReclassificationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RestatementDomain_f85b5c6e-7ff8-4bc9-b466-08cc526c329a" xlink:to="loc_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember_5b74450f-33a8-43dd-95e9-27ebf9c876ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_1ca730fb-f71a-4f29-a7f0-43b3fb110625" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_1ca730fb-f71a-4f29-a7f0-43b3fb110625" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1ca730fb-f71a-4f29-a7f0-43b3fb110625_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_1ca730fb-f71a-4f29-a7f0-43b3fb110625" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1ca730fb-f71a-4f29-a7f0-43b3fb110625_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8710046d-0bd7-4981-9263-9360cf5dc243" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_1ca730fb-f71a-4f29-a7f0-43b3fb110625" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8710046d-0bd7-4981-9263-9360cf5dc243" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_c0f91d7c-e4b0-4ffd-b702-a0de026057d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8710046d-0bd7-4981-9263-9360cf5dc243" xlink:to="loc_us-gaap_AccountsReceivableMember_c0f91d7c-e4b0-4ffd-b702-a0de026057d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_1f85d5a6-8138-4349-9612-1342e463afd3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_1f85d5a6-8138-4349-9612-1342e463afd3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_1f85d5a6-8138-4349-9612-1342e463afd3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_1f85d5a6-8138-4349-9612-1342e463afd3" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_1f85d5a6-8138-4349-9612-1342e463afd3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_bd823694-ced7-4b17-b915-07153aee2de9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_1f85d5a6-8138-4349-9612-1342e463afd3" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_bd823694-ced7-4b17-b915-07153aee2de9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_e0d7236b-2c46-43e3-825e-d698a5a9bef2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_bd823694-ced7-4b17-b915-07153aee2de9" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_e0d7236b-2c46-43e3-825e-d698a5a9bef2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_02e22539-a0c7-464e-a52c-21303405d1c8" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:to="loc_srt_MajorCustomersAxis_02e22539-a0c7-464e-a52c-21303405d1c8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_02e22539-a0c7-464e-a52c-21303405d1c8_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_02e22539-a0c7-464e-a52c-21303405d1c8" xlink:to="loc_srt_NameOfMajorCustomerDomain_02e22539-a0c7-464e-a52c-21303405d1c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_844b082a-b8f0-48e0-87bf-3f4706aa3a70" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_02e22539-a0c7-464e-a52c-21303405d1c8" xlink:to="loc_srt_NameOfMajorCustomerDomain_844b082a-b8f0-48e0-87bf-3f4706aa3a70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_MedicareMember_93ef47e6-8fb1-4e2a-a230-e1ead975a1a4" xlink:href="vcyt-20220630.xsd#vcyt_MedicareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_844b082a-b8f0-48e0-87bf-3f4706aa3a70" xlink:to="loc_vcyt_MedicareMember_93ef47e6-8fb1-4e2a-a230-e1ead975a1a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_05146705-c84d-45a6-a461-baca230d7fb1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_a55d762e-029c-47fd-a643-490bb29220cd" xlink:to="loc_srt_ProductOrServiceAxis_05146705-c84d-45a6-a461-baca230d7fb1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_05146705-c84d-45a6-a461-baca230d7fb1_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_05146705-c84d-45a6-a461-baca230d7fb1" xlink:to="loc_srt_ProductsAndServicesDomain_05146705-c84d-45a6-a461-baca230d7fb1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_719d8f8f-9190-40ff-bcaa-708d8f8db094" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_05146705-c84d-45a6-a461-baca230d7fb1" xlink:to="loc_srt_ProductsAndServicesDomain_719d8f8f-9190-40ff-bcaa-708d8f8db094" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BiopharmaceuticalAndOtherMember_430d1271-db85-4d38-a479-4edad5461f3c" xlink:href="vcyt-20220630.xsd#vcyt_BiopharmaceuticalAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_719d8f8f-9190-40ff-bcaa-708d8f8db094" xlink:to="loc_vcyt_BiopharmaceuticalAndOtherMember_430d1271-db85-4d38-a479-4edad5461f3c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofThirdpartyPayersAndOtherCustomersDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofThirdpartyPayersAndOtherCustomersDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofThirdpartyPayersAndOtherCustomersDetails" xlink:type="extended" id="i9699ae224f904c58ab560ad9a43a7baf_OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofThirdpartyPayersAndOtherCustomersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_b0f30ada-6805-4ab9-aead-ab5abc59f917" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_72a2aa8a-71c0-4595-a8ff-1c20dd887b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_b0f30ada-6805-4ab9-aead-ab5abc59f917" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_72a2aa8a-71c0-4595-a8ff-1c20dd887b9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_f88c7441-63e1-4b9f-888c-fbe5cd265211" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_b0f30ada-6805-4ab9-aead-ab5abc59f917" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_f88c7441-63e1-4b9f-888c-fbe5cd265211" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_783f7f08-635b-43d8-b564-78f8b271d87c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_f88c7441-63e1-4b9f-888c-fbe5cd265211" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_783f7f08-635b-43d8-b564-78f8b271d87c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_783f7f08-635b-43d8-b564-78f8b271d87c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_783f7f08-635b-43d8-b564-78f8b271d87c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_783f7f08-635b-43d8-b564-78f8b271d87c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_6585aea0-7e0a-4a8d-ad85-23c452201d83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_783f7f08-635b-43d8-b564-78f8b271d87c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_6585aea0-7e0a-4a8d-ad85-23c452201d83" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_847728ea-4538-4574-8205-ce2ae28c6f9a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_6585aea0-7e0a-4a8d-ad85-23c452201d83" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_847728ea-4538-4574-8205-ce2ae28c6f9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_f88c7441-63e1-4b9f-888c-fbe5cd265211" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8e8168b9-e687-4556-9bb3-6902c65752c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_26aa5ddc-5c8a-40ab-9e60-49c54fad0a0b" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8e8168b9-e687-4556-9bb3-6902c65752c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_81e2aeb6-321f-4a93-9399-37bd8287e123" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8e8168b9-e687-4556-9bb3-6902c65752c9" xlink:to="loc_us-gaap_SalesRevenueNetMember_81e2aeb6-321f-4a93-9399-37bd8287e123" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_6a99b84a-2900-4fcc-b0d5-12905de922cf" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_f88c7441-63e1-4b9f-888c-fbe5cd265211" xlink:to="loc_srt_MajorCustomersAxis_6a99b84a-2900-4fcc-b0d5-12905de922cf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6a99b84a-2900-4fcc-b0d5-12905de922cf_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_6a99b84a-2900-4fcc-b0d5-12905de922cf" xlink:to="loc_srt_NameOfMajorCustomerDomain_6a99b84a-2900-4fcc-b0d5-12905de922cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_5bc9729e-ff5a-4fce-9a47-dde45963188c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_6a99b84a-2900-4fcc-b0d5-12905de922cf" xlink:to="loc_srt_NameOfMajorCustomerDomain_5bc9729e-ff5a-4fce-9a47-dde45963188c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_MedicareMember_5246c262-4748-4c55-ada7-7afe2d428e51" xlink:href="vcyt-20220630.xsd#vcyt_MedicareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_5bc9729e-ff5a-4fce-9a47-dde45963188c" xlink:to="loc_vcyt_MedicareMember_5246c262-4748-4c55-ada7-7afe2d428e51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_UnitedHealthcareMember_5ce65f0f-74e1-4108-afbd-959e2258a73a" xlink:href="vcyt-20220630.xsd#vcyt_UnitedHealthcareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_5bc9729e-ff5a-4fce-9a47-dde45963188c" xlink:to="loc_vcyt_UnitedHealthcareMember_5ce65f0f-74e1-4108-afbd-959e2258a73a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_MajorCustomersMember_8e88c803-b5a5-4207-9270-437e6ca137bb" xlink:href="vcyt-20220630.xsd#vcyt_MajorCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_5bc9729e-ff5a-4fce-9a47-dde45963188c" xlink:to="loc_vcyt_MajorCustomersMember_8e88c803-b5a5-4207-9270-437e6ca137bb" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofBiopharmaceuticalandOtherRevenuesDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofBiopharmaceuticalandOtherRevenuesDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofBiopharmaceuticalandOtherRevenuesDetails" xlink:type="extended" id="ie2b3f03c33984c868934e579293ca6a5_OrganizationDescriptionofBusinessandSummaryofSignificantAccountingPoliciesScheduleofBiopharmaceuticalandOtherRevenuesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_5aa1582f-9e51-42cc-b170-f80cff721e8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b76e55dc-73f3-4818-9ecf-38fa5afda27b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5aa1582f-9e51-42cc-b170-f80cff721e8f" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b76e55dc-73f3-4818-9ecf-38fa5afda27b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_40d7aee5-e144-450a-871b-0d6e39e17159" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5aa1582f-9e51-42cc-b170-f80cff721e8f" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_40d7aee5-e144-450a-871b-0d6e39e17159" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_7779088e-b75f-494f-9360-2db244285267" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_40d7aee5-e144-450a-871b-0d6e39e17159" xlink:to="loc_srt_ProductOrServiceAxis_7779088e-b75f-494f-9360-2db244285267" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7779088e-b75f-494f-9360-2db244285267_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_7779088e-b75f-494f-9360-2db244285267" xlink:to="loc_srt_ProductsAndServicesDomain_7779088e-b75f-494f-9360-2db244285267_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_742e57df-56ca-470b-8c1f-b6dfb6116e5d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_7779088e-b75f-494f-9360-2db244285267" xlink:to="loc_srt_ProductsAndServicesDomain_742e57df-56ca-470b-8c1f-b6dfb6116e5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BiopharmaceuticalAndOtherBiopharmaceuticalRevenueMember_8c9fad5a-5c6f-4c66-8d6b-d2b9b0872d63" xlink:href="vcyt-20220630.xsd#vcyt_BiopharmaceuticalAndOtherBiopharmaceuticalRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_742e57df-56ca-470b-8c1f-b6dfb6116e5d" xlink:to="loc_vcyt_BiopharmaceuticalAndOtherBiopharmaceuticalRevenueMember_8c9fad5a-5c6f-4c66-8d6b-d2b9b0872d63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BiopharmaceuticalAndOtherContractManufacturingAndTestingMember_6120bcab-e277-4bea-b36d-ece79d92175f" xlink:href="vcyt-20220630.xsd#vcyt_BiopharmaceuticalAndOtherContractManufacturingAndTestingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_742e57df-56ca-470b-8c1f-b6dfb6116e5d" xlink:to="loc_vcyt_BiopharmaceuticalAndOtherContractManufacturingAndTestingMember_6120bcab-e277-4bea-b36d-ece79d92175f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BiopharmaceuticalAndOtherMember_3741e70a-4846-4df9-a562-a9c0ef270f24" xlink:href="vcyt-20220630.xsd#vcyt_BiopharmaceuticalAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_742e57df-56ca-470b-8c1f-b6dfb6116e5d" xlink:to="loc_vcyt_BiopharmaceuticalAndOtherMember_3741e70a-4846-4df9-a562-a9c0ef270f24" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/NetLossPerCommonShareDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#NetLossPerCommonShareDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/NetLossPerCommonShareDetails" xlink:type="extended" id="i4e4223e02b8f46d98b4a1ce7fb7d5b85_NetLossPerCommonShareDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1efa7c77-66ab-4e6b-b1c6-899af204679f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_86ca200a-36af-44aa-8f07-03c4f19c3025" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1efa7c77-66ab-4e6b-b1c6-899af204679f" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_86ca200a-36af-44aa-8f07-03c4f19c3025" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_771b6ddd-8da0-4e4f-803d-eec5095deffc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1efa7c77-66ab-4e6b-b1c6-899af204679f" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_771b6ddd-8da0-4e4f-803d-eec5095deffc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_bb96d3be-7d66-4bd2-a660-c6c7c78124b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_771b6ddd-8da0-4e4f-803d-eec5095deffc" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_bb96d3be-7d66-4bd2-a660-c6c7c78124b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_bb96d3be-7d66-4bd2-a660-c6c7c78124b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_bb96d3be-7d66-4bd2-a660-c6c7c78124b9" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_bb96d3be-7d66-4bd2-a660-c6c7c78124b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8bf76af1-a7af-422d-9628-1dcfcd0b27a3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_bb96d3be-7d66-4bd2-a660-c6c7c78124b9" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8bf76af1-a7af-422d-9628-1dcfcd0b27a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_EmployeeAndNonEmployeeStockOptionMember_1e982e12-8fa5-4a7c-896d-e3b53c9a8020" xlink:href="vcyt-20220630.xsd#vcyt_EmployeeAndNonEmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8bf76af1-a7af-422d-9628-1dcfcd0b27a3" xlink:to="loc_vcyt_EmployeeAndNonEmployeeStockOptionMember_1e982e12-8fa5-4a7c-896d-e3b53c9a8020" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_5954a173-2847-4155-aea7-1d238fcbad1f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8bf76af1-a7af-422d-9628-1dcfcd0b27a3" xlink:to="loc_us-gaap_EmployeeStockMember_5954a173-2847-4155-aea7-1d238fcbad1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_2f80c06f-dfa7-40ee-b8e2-746966814527" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8bf76af1-a7af-422d-9628-1dcfcd0b27a3" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_2f80c06f-dfa7-40ee-b8e2-746966814527" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/BalanceSheetComponentsNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#BalanceSheetComponentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/BalanceSheetComponentsNarrativeDetails" xlink:type="extended" id="i8c704221e07248f881c61555678eb32e_BalanceSheetComponentsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_9f56466d-0f9a-40b8-af9a-c8cac1bc4574" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_Goodwill_9f56466d-0f9a-40b8-af9a-c8cac1bc4574" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_02694e01-1e6d-4fcb-9c7a-e466a600d7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_02694e01-1e6d-4fcb-9c7a-e466a600d7a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_30fad3d9-bed6-4652-99d8-82a28a671974" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_30fad3d9-bed6-4652-99d8-82a28a671974" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryFinishedGoods_45f24e3d-c6e3-4139-9734-d93f11f23faa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryFinishedGoods"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_InventoryFinishedGoods_45f24e3d-c6e3-4139-9734-d93f11f23faa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWorkInProcessAndRawMaterials_42098425-6665-4a60-89fe-0f92cbc20b10" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryWorkInProcessAndRawMaterials"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_InventoryWorkInProcessAndRawMaterials_42098425-6665-4a60-89fe-0f92cbc20b10" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_45cb3da4-299d-48f4-af78-96afe100f726" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7017e55b-a340-4cb8-be86-744cabb0fca5" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_45cb3da4-299d-48f4-af78-96afe100f726" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2d787487-191d-484e-88fa-a73a85aa722f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_45cb3da4-299d-48f4-af78-96afe100f726" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2d787487-191d-484e-88fa-a73a85aa722f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2d787487-191d-484e-88fa-a73a85aa722f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2d787487-191d-484e-88fa-a73a85aa722f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2d787487-191d-484e-88fa-a73a85aa722f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3d669c5b-ba18-4ca1-847c-e8e71889df47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2d787487-191d-484e-88fa-a73a85aa722f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3d669c5b-ba18-4ca1-847c-e8e71889df47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDXDevelopedTechnologyMember_6d3d46e3-a1b4-4c21-9570-aeafd6ae00f7" xlink:href="vcyt-20220630.xsd#vcyt_HalioDXDevelopedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3d669c5b-ba18-4ca1-847c-e8e71889df47" xlink:to="loc_vcyt_HalioDXDevelopedTechnologyMember_6d3d46e3-a1b4-4c21-9570-aeafd6ae00f7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/BalanceSheetComponentsScheduleofIntangibleAssetsDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#BalanceSheetComponentsScheduleofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/BalanceSheetComponentsScheduleofIntangibleAssetsDetails" xlink:type="extended" id="i2ee20f5f548245c88f12ec3bc6545fc1_BalanceSheetComponentsScheduleofIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_bb5fb7f5-ddf9-416a-8226-3da9b34e3a4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_bb5fb7f5-ddf9-416a-8226-3da9b34e3a4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_7b1996f0-f024-487c-af46-f4b4ed3ce3f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_7b1996f0-f024-487c-af46-f4b4ed3ce3f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_fafafe34-c7a8-4418-94da-a705f027169d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_fafafe34-c7a8-4418-94da-a705f027169d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_b8d56b56-a032-4ab6-9e91-25f106f1a275" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_b8d56b56-a032-4ab6-9e91-25f106f1a275" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_3c579d76-a853-46ba-82f6-69a783cdaa78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_3c579d76-a853-46ba-82f6-69a783cdaa78" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_85315e3a-6519-4913-b786-db1e9d31c954" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_85315e3a-6519-4913-b786-db1e9d31c954" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_b69a8dfb-ad7b-40e8-8239-f97b25e8f6a8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_b69a8dfb-ad7b-40e8-8239-f97b25e8f6a8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8aebc9b3-8562-4fce-8b57-a06f7d227c73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e3f0af8d-cfec-4617-a514-f093c0b6be8f" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8aebc9b3-8562-4fce-8b57-a06f7d227c73" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8aebc9b3-8562-4fce-8b57-a06f7d227c73" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0402d6cb-fbb1-448c-aeac-9ca3ac8dabec" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_PerceptaProductTechnologyMember_e3a53564-fc4f-4504-9b9c-f1b888a5076d" xlink:href="vcyt-20220630.xsd#vcyt_PerceptaProductTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_PerceptaProductTechnologyMember_e3a53564-fc4f-4504-9b9c-f1b888a5076d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DevelopedProductTechnologyMember_21c536be-c358-4cb6-b50a-d7908235e543" xlink:href="vcyt-20220630.xsd#vcyt_DevelopedProductTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_DevelopedProductTechnologyMember_21c536be-c358-4cb6-b50a-d7908235e543" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_ProsignaCustomerRelationshipsMember_aad92bbb-fe75-47ad-bef1-ab12292a92eb" xlink:href="vcyt-20220630.xsd#vcyt_ProsignaCustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_ProsignaCustomerRelationshipsMember_aad92bbb-fe75-47ad-bef1-ab12292a92eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_NCounterDxLicenseMember_73d98773-87e6-4f3a-870f-a0ade7460183" xlink:href="vcyt-20220630.xsd#vcyt_NCounterDxLicenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_NCounterDxLicenseMember_73d98773-87e6-4f3a-870f-a0ade7460183" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_LymphmarkProductTechnologyMember_66545ae2-c25b-44be-b60d-0617874197fd" xlink:href="vcyt-20220630.xsd#vcyt_LymphmarkProductTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_LymphmarkProductTechnologyMember_66545ae2-c25b-44be-b60d-0617874197fd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DecipherBioSciencesProductTechnologyMember_6909a589-2632-47b7-a008-a862e2c6d402" xlink:href="vcyt-20220630.xsd#vcyt_DecipherBioSciencesProductTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_DecipherBioSciencesProductTechnologyMember_6909a589-2632-47b7-a008-a862e2c6d402" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DecipherBiosciencesTradeNamesMember_0e55c44b-56c0-4cbd-b63f-4a9d291b4a19" xlink:href="vcyt-20220630.xsd#vcyt_DecipherBiosciencesTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_DecipherBiosciencesTradeNamesMember_0e55c44b-56c0-4cbd-b63f-4a9d291b4a19" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDXDevelopedTechnologyMember_7ce1ec15-b87a-4fb5-99aa-879d32954455" xlink:href="vcyt-20220630.xsd#vcyt_HalioDXDevelopedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_HalioDXDevelopedTechnologyMember_7ce1ec15-b87a-4fb5-99aa-879d32954455" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxCustomerRelationshipsMember_9a104827-111a-4d1e-a9ba-01e86e670715" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxCustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_HalioDxCustomerRelationshipsMember_9a104827-111a-4d1e-a9ba-01e86e670715" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxCustomerBacklogMember_a7236686-d013-4a09-a25d-1c80e4dced63" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxCustomerBacklogMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45055d4a-505e-4ee9-beb7-d92b2123802f" xlink:to="loc_vcyt_HalioDxCustomerBacklogMember_a7236686-d013-4a09-a25d-1c80e4dced63" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/BusinessCombinationsNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#BusinessCombinationsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/BusinessCombinationsNarrativeDetails" xlink:type="extended" id="i16f081a58c0a4cbcb42a777f8dea0878_BusinessCombinationsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_0ed430c0-2e5f-4fda-8db1-9aee976b4234" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_0ed430c0-2e5f-4fda-8db1-9aee976b4234" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_d219a367-623e-4797-a4e5-3043c83a5f98" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_d219a367-623e-4797-a4e5-3043c83a5f98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_67d67c35-8233-4b49-abb1-a5f07ce6b2de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_67d67c35-8233-4b49-abb1-a5f07ce6b2de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_129507d3-ba3d-4d8b-86a2-59346b2ecaab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_129507d3-ba3d-4d8b-86a2-59346b2ecaab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_5d17f093-1413-4cce-874b-7363556d7098" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_5d17f093-1413-4cce-874b-7363556d7098" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_5a0d3db1-3428-4832-b3ca-d276af16fb82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_5a0d3db1-3428-4832-b3ca-d276af16fb82" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_2d32601d-a8eb-4afb-b2ca-627c3859f216" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_2d32601d-a8eb-4afb-b2ca-627c3859f216" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e110e2b3-4910-4a44-9391-74e838990c2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_55ec0a28-ccbf-487c-9d66-0b261fd8368d" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e110e2b3-4910-4a44-9391-74e838990c2f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_375dc940-6df6-42f3-8138-6a630abf48f4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e110e2b3-4910-4a44-9391-74e838990c2f" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_375dc940-6df6-42f3-8138-6a630abf48f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_375dc940-6df6-42f3-8138-6a630abf48f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_375dc940-6df6-42f3-8138-6a630abf48f4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_375dc940-6df6-42f3-8138-6a630abf48f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_375dc940-6df6-42f3-8138-6a630abf48f4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxSASMember_9ff96e08-fa21-4ee1-8a97-b3e4bb10f66e" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxSASMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:to="loc_vcyt_HalioDxSASMember_9ff96e08-fa21-4ee1-8a97-b3e4bb10f66e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxIncMember_cb241c29-48a4-40d8-b11d-84968d6c52fc" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:to="loc_vcyt_HalioDxIncMember_cb241c29-48a4-40d8-b11d-84968d6c52fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxMember_cf1a8c4a-2421-4b2c-a6e2-745aed7d779e" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:to="loc_vcyt_HalioDxMember_cf1a8c4a-2421-4b2c-a6e2-745aed7d779e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DecipherBiosciencesMember_e5064c9d-3776-4d1e-89e8-b562ccf1747c" xlink:href="vcyt-20220630.xsd#vcyt_DecipherBiosciencesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_73d455d7-2c25-4c96-912e-2bd1f9a49d1d" xlink:to="loc_vcyt_DecipherBiosciencesMember_e5064c9d-3776-4d1e-89e8-b562ccf1747c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e9cd4803-f848-482d-be84-3cca27a7378e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e110e2b3-4910-4a44-9391-74e838990c2f" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e9cd4803-f848-482d-be84-3cca27a7378e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e9cd4803-f848-482d-be84-3cca27a7378e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e9cd4803-f848-482d-be84-3cca27a7378e" xlink:to="loc_us-gaap_RelatedPartyDomain_e9cd4803-f848-482d-be84-3cca27a7378e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_35fd351f-a465-48fb-a754-d2af1f384009" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_e9cd4803-f848-482d-be84-3cca27a7378e" xlink:to="loc_us-gaap_RelatedPartyDomain_35fd351f-a465-48fb-a754-d2af1f384009" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DrTinaSNovaPhDMember_bbff1443-15d3-4a34-978b-6eb054a50c55" xlink:href="vcyt-20220630.xsd#vcyt_DrTinaSNovaPhDMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_35fd351f-a465-48fb-a754-d2af1f384009" xlink:to="loc_vcyt_DrTinaSNovaPhDMember_bbff1443-15d3-4a34-978b-6eb054a50c55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DrRobertSEpsteinMDMSMember_23130fec-18ff-4b70-a63a-4775e2b89e48" xlink:href="vcyt-20220630.xsd#vcyt_DrRobertSEpsteinMDMSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_35fd351f-a465-48fb-a754-d2af1f384009" xlink:to="loc_vcyt_DrRobertSEpsteinMDMSMember_23130fec-18ff-4b70-a63a-4775e2b89e48" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/BusinessCombinationsFairValuesofAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#BusinessCombinationsFairValuesofAssetsAcquiredandLiabilitiesAssumedDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/BusinessCombinationsFairValuesofAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="extended" id="i7346eb15842546ce8c1662e3b59c59c0_BusinessCombinationsFairValuesofAssetsAcquiredandLiabilitiesAssumedDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_2eed92f2-bda9-4a74-bab7-ce7fdb761eb1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_2eed92f2-bda9-4a74-bab7-ce7fdb761eb1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_c06fb9be-32df-466d-8bfb-a64ddb6f1a8a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_c06fb9be-32df-466d-8bfb-a64ddb6f1a8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_9ebae084-a6c1-414d-ba72-856945c4bfb4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_9ebae084-a6c1-414d-ba72-856945c4bfb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_16e3dbae-00be-4a0f-9a8a-f5496e567574" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_16e3dbae-00be-4a0f-9a8a-f5496e567574" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_7703692a-0de1-4153-aff3-0fefdfb0bba2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_7703692a-0de1-4153-aff3-0fefdfb0bba2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancingLeaseRightOfUseAsset_6213b509-fcd1-4de2-9067-647822e232fd" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancingLeaseRightOfUseAsset_6213b509-fcd1-4de2-9067-647822e232fd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset_517d3dc8-1e12-42d9-8639-9d39132eee56" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset_517d3dc8-1e12-42d9-8639-9d39132eee56" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_8d8bb38d-03c9-479a-b8fb-fd23f358d911" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_8d8bb38d-03c9-479a-b8fb-fd23f358d911" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_2cb224b6-0e05-4abc-a800-b9d3668d0663" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_2cb224b6-0e05-4abc-a800-b9d3668d0663" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash_7a584458-ae1d-434f-9f0e-05e0eb85930f" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash_7a584458-ae1d-434f-9f0e-05e0eb85930f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherAssets_a450141d-7fcd-46de-9efd-0f7a913c491a" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherAssets_a450141d-7fcd-46de-9efd-0f7a913c491a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_0c965e24-85e7-4e57-a95f-f6237fe5f6c7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_0c965e24-85e7-4e57-a95f-f6237fe5f6c7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_d9910947-436f-4d41-8cef-d190c67ebec6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_d9910947-436f-4d41-8cef-d190c67ebec6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedLiabilities_9961a973-d934-479c-b74d-79437bf14920" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedLiabilities_9961a973-d934-479c-b74d-79437bf14920" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentFinancingLeaseLiability_29bf6b2e-7907-4b6b-861c-eb93f0966b53" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentFinancingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentFinancingLeaseLiability_29bf6b2e-7907-4b6b-861c-eb93f0966b53" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentOperatingLeaseLiability_7898c554-8b84-4f83-a91d-471c8769d25a" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedCurrentOperatingLeaseLiability_7898c554-8b84-4f83-a91d-471c8769d25a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt_9d877d1e-6cec-41d3-ac67-48bfed547844" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt_9d877d1e-6cec-41d3-ac67-48bfed547844" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_6b2a02ed-8142-4ab9-8fe7-4c4128f3d55c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_6b2a02ed-8142-4ab9-8fe7-4c4128f3d55c" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedFinancingLeaseLiability_2a4588a4-491a-430a-b5b6-b48ec5d8fa53" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedFinancingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedFinancingLeaseLiability_2a4588a4-491a-430a-b5b6-b48ec5d8fa53" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedOperatingLeaseLiability_c112a02c-1837-47eb-b100-7bb87b57467b" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedOperatingLeaseLiability_c112a02c-1837-47eb-b100-7bb87b57467b" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_b509e582-401b-404a-8eef-b02fd4082ac2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_b509e582-401b-404a-8eef-b02fd4082ac2" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_b417d9f2-f0ee-432c-8d33-edcffc577419" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_b417d9f2-f0ee-432c-8d33-edcffc577419" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_5eb6a00b-70c3-4e43-b9d1-5e550a68fd15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_Goodwill_5eb6a00b-70c3-4e43-b9d1-5e550a68fd15" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_fc827729-f4fb-467a-913c-72b987afef5b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_fc827729-f4fb-467a-913c-72b987afef5b" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fb265910-f078-42f5-bfe6-d3acabb0b4d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9993fb8f-da02-4ca5-bdd6-737e09bd1b9b" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fb265910-f078-42f5-bfe6-d3acabb0b4d0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_6cef2e0b-de98-4523-bec0-9d26a0fef02b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fb265910-f078-42f5-bfe6-d3acabb0b4d0" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_6cef2e0b-de98-4523-bec0-9d26a0fef02b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6cef2e0b-de98-4523-bec0-9d26a0fef02b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6cef2e0b-de98-4523-bec0-9d26a0fef02b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6cef2e0b-de98-4523-bec0-9d26a0fef02b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ddd0457c-d9f4-4409-ba8e-ec990706bf66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6cef2e0b-de98-4523-bec0-9d26a0fef02b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ddd0457c-d9f4-4409-ba8e-ec990706bf66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HalioDxMember_73caa6a6-f727-4476-8c8f-4d6de44ec56d" xlink:href="vcyt-20220630.xsd#vcyt_HalioDxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ddd0457c-d9f4-4409-ba8e-ec990706bf66" xlink:to="loc_vcyt_HalioDxMember_73caa6a6-f727-4476-8c8f-4d6de44ec56d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DecipherBiosciencesMember_23c2c828-567c-4ce0-a7e7-0888b6eee32b" xlink:href="vcyt-20220630.xsd#vcyt_DecipherBiosciencesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ddd0457c-d9f4-4409-ba8e-ec990706bf66" xlink:to="loc_vcyt_DecipherBiosciencesMember_23c2c828-567c-4ce0-a7e7-0888b6eee32b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#FairValueMeasurementsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended" id="i2dc5c8769e454bc284ba14e56ed10cba_FairValueMeasurementsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7f1dae29-f032-4671-853b-860522096874" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7f1dae29-f032-4671-853b-860522096874" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDeposit_12b74f5c-7eb0-4c2b-a426-f25116582b55" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecurityDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_SecurityDeposit_12b74f5c-7eb0-4c2b-a426-f25116582b55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_9cc0615d-0f0f-4c1f-bfc8-5d3f1ec70115" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_9cc0615d-0f0f-4c1f-bfc8-5d3f1ec70115" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_a5c471bc-3565-45ac-9549-f60b5afe310b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_a5c471bc-3565-45ac-9549-f60b5afe310b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationContingentConsiderationCashToBePaid_5d113e15-da20-4502-80d9-ead420185916" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationContingentConsiderationCashToBePaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_vcyt_BusinessCombinationContingentConsiderationCashToBePaid_5d113e15-da20-4502-80d9-ead420185916" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_6089481b-43b8-4f1a-bd2f-05654078aedd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_6089481b-43b8-4f1a-bd2f-05654078aedd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationContingentConsiderationLiabilityFairValueAdjustment_3f303ba7-2b6c-40bf-a9f4-faf566ec896d" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationContingentConsiderationLiabilityFairValueAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_vcyt_BusinessCombinationContingentConsiderationLiabilityFairValueAdjustment_3f303ba7-2b6c-40bf-a9f4-faf566ec896d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_95b8daee-6973-4db9-8a40-08001cd83e3c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_95b8daee-6973-4db9-8a40-08001cd83e3c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_4bd71ad4-163e-4065-a7f3-8a9c645dfd7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_4bd71ad4-163e-4065-a7f3-8a9c645dfd7a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_6e51b4a9-1bdc-4ddb-92e0-e7553c70d858" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_6e51b4a9-1bdc-4ddb-92e0-e7553c70d858" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b0a35314-015e-4a4e-a08d-7511aa1cadff" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_023b1b9d-34f9-4e91-9204-39b2cc3c437e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:to="loc_us-gaap_FinancialInstrumentAxis_023b1b9d-34f9-4e91-9204-39b2cc3c437e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023b1b9d-34f9-4e91-9204-39b2cc3c437e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_023b1b9d-34f9-4e91-9204-39b2cc3c437e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023b1b9d-34f9-4e91-9204-39b2cc3c437e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e5dcf80e-4d51-4fc9-a9d3-c482073bd8e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_023b1b9d-34f9-4e91-9204-39b2cc3c437e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e5dcf80e-4d51-4fc9-a9d3-c482073bd8e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_64326084-1c8d-4f70-8ac5-a8195122ebda" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e5dcf80e-4d51-4fc9-a9d3-c482073bd8e0" xlink:to="loc_us-gaap_MoneyMarketFundsMember_64326084-1c8d-4f70-8ac5-a8195122ebda" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermAxis_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseContractualTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:to="loc_us-gaap_LeaseContractualTermAxis_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LeaseContractualTermAxis_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9" xlink:to="loc_us-gaap_LeaseContractualTermDomain_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_abba95d4-5afb-42e2-b1de-f30f9df2bab0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LeaseContractualTermAxis_25b0efd6-8ba6-4f0b-9fbb-f227f0d6c7d9" xlink:to="loc_us-gaap_LeaseContractualTermDomain_abba95d4-5afb-42e2-b1de-f30f9df2bab0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoMember_188ec43a-e5cf-40ff-9cb5-daa0fe8011fc" xlink:href="vcyt-20220630.xsd#vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseContractualTermDomain_abba95d4-5afb-42e2-b1de-f30f9df2bab0" xlink:to="loc_vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoMember_188ec43a-e5cf-40ff-9cb5-daa0fe8011fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d1801b2a-d545-4425-a3b8-d7c3d6dd4553" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fd6e8c9b-98a6-4862-baa6-c7e5d3e5d07d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d1801b2a-d545-4425-a3b8-d7c3d6dd4553" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_NanostringMember_3f147edc-c8d3-4746-9afe-742f803b8692" xlink:href="vcyt-20220630.xsd#vcyt_NanostringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d1801b2a-d545-4425-a3b8-d7c3d6dd4553" xlink:to="loc_vcyt_NanostringMember_3f147edc-c8d3-4746-9afe-742f803b8692" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_54ad1d41-9035-4ee7-abbf-72e6f129a776" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityInterestIssuedOrIssuableByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_7fd8e1f0-5617-487d-97ec-66e1149b9e4d" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_54ad1d41-9035-4ee7-abbf-72e6f129a776" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_54ad1d41-9035-4ee7-abbf-72e6f129a776_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityInterestIssuedOrIssuableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_54ad1d41-9035-4ee7-abbf-72e6f129a776" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_54ad1d41-9035-4ee7-abbf-72e6f129a776_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_85114939-987a-4967-a5dd-9b8756e2b40f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityInterestIssuedOrIssuableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_54ad1d41-9035-4ee7-abbf-72e6f129a776" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_85114939-987a-4967-a5dd-9b8756e2b40f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_7c0b6748-87ee-45e0-8163-50699b129197" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_85114939-987a-4967-a5dd-9b8756e2b40f" xlink:to="loc_us-gaap_CommonStockMember_7c0b6748-87ee-45e0-8163-50699b129197" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/FairValueMeasurementsFairValueMeasurementInputDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#FairValueMeasurementsFairValueMeasurementInputDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/FairValueMeasurementsFairValueMeasurementInputDetails" xlink:type="extended" id="i2ab248fe836948d896441723f2ac1cee_FairValueMeasurementsFairValueMeasurementInputDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_10107e41-d08f-43b5-bea8-e9c75f5774f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_4db39183-fa3c-4e3e-bf59-2ff6369b9369" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_10107e41-d08f-43b5-bea8-e9c75f5774f2" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_4db39183-fa3c-4e3e-bf59-2ff6369b9369" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_c4eb643f-4272-4af5-a372-a27ad268fbae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_10107e41-d08f-43b5-bea8-e9c75f5774f2" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_c4eb643f-4272-4af5-a372-a27ad268fbae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_f16709c7-6182-41be-8aa5-b22663738175" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_c4eb643f-4272-4af5-a372-a27ad268fbae" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_f16709c7-6182-41be-8aa5-b22663738175" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_f16709c7-6182-41be-8aa5-b22663738175_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_f16709c7-6182-41be-8aa5-b22663738175" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_f16709c7-6182-41be-8aa5-b22663738175_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_441ac48e-f361-491d-a941-25c0bd73460d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_f16709c7-6182-41be-8aa5-b22663738175" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_441ac48e-f361-491d-a941-25c0bd73460d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_4a8968b4-6048-4d20-aba8-e4d0e1d3cc99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_441ac48e-f361-491d-a941-25c0bd73460d" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_4a8968b4-6048-4d20-aba8-e4d0e1d3cc99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_MeasurementInputProbabilityOfAchievementMember_adad7fc5-be34-4a25-9057-aecc1ce4fe02" xlink:href="vcyt-20220630.xsd#vcyt_MeasurementInputProbabilityOfAchievementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_441ac48e-f361-491d-a941-25c0bd73460d" xlink:to="loc_vcyt_MeasurementInputProbabilityOfAchievementMember_adad7fc5-be34-4a25-9057-aecc1ce4fe02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_c4eb643f-4272-4af5-a372-a27ad268fbae" xlink:to="loc_srt_RangeAxis_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe" xlink:to="loc_srt_RangeMember_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5e1fdc36-9629-4535-aa72-064e885b69aa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_6d0899a7-fbbe-4a8a-93db-e87758a8e7fe" xlink:to="loc_srt_RangeMember_5e1fdc36-9629-4535-aa72-064e885b69aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_ce0a0121-9643-42b4-8a05-c69f870c0126" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5e1fdc36-9629-4535-aa72-064e885b69aa" xlink:to="loc_srt_MinimumMember_ce0a0121-9643-42b4-8a05-c69f870c0126" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6b746570-124f-486e-9c36-0b43d3892b82" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5e1fdc36-9629-4535-aa72-064e885b69aa" xlink:to="loc_srt_MaximumMember_6b746570-124f-486e-9c36-0b43d3892b82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_bb4f8259-f64b-4476-9f3b-cb108de20d12" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5e1fdc36-9629-4535-aa72-064e885b69aa" xlink:to="loc_srt_WeightedAverageMember_bb4f8259-f64b-4476-9f3b-cb108de20d12" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#CommitmentsandContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="extended" id="iee36e174ff494c11b6c5578af8e5cc63_CommitmentsandContingenciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeasedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_2ecae2ec-cd9f-458e-abea-480e3ab8e805" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_2ecae2ec-cd9f-458e-abea-480e3ab8e805" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDeposit_be761307-24f4-4dff-bd2d-a9f8b84613fd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecurityDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_SecurityDeposit_be761307-24f4-4dff-bd2d-a9f8b84613fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_cf5ac1d3-2458-4616-94fc-2d7ba455ebaf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_cf5ac1d3-2458-4616-94fc-2d7ba455ebaf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset_62b0c57e-4ff1-463c-8439-5b043d5b5278" xlink:href="vcyt-20220630.xsd#vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_vcyt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAsset_62b0c57e-4ff1-463c-8439-5b043d5b5278" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset_17296480-a682-4856-9c0d-d8cc72a4fb5d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAsset_17296480-a682-4856-9c0d-d8cc72a4fb5d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_c4a0acd1-5a80-41f3-9ea6-38c9b5435c33" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAsset_17296480-a682-4856-9c0d-d8cc72a4fb5d" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_c4a0acd1-5a80-41f3-9ea6-38c9b5435c33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_e62a226d-3137-460b-a122-fd7b74e10163" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_FinanceLeaseLiability_e62a226d-3137-460b-a122-fd7b74e10163" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_3788ab48-3eec-4414-b1c4-a756c5e062c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinanceLeaseLiability_e62a226d-3137-460b-a122-fd7b74e10163" xlink:to="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_3788ab48-3eec-4414-b1c4-a756c5e062c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_8e99d847-9996-4b4c-a056-7835f880b069" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_8e99d847-9996-4b4c-a056-7835f880b069" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_LesseeOperatingLeaseLeaseNotYetCommencedAnnualUndiscountedAmount_57d44576-c91e-49c7-8ad6-bb0f08ca196b" xlink:href="vcyt-20220630.xsd#vcyt_LesseeOperatingLeaseLeaseNotYetCommencedAnnualUndiscountedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_vcyt_LesseeOperatingLeaseLeaseNotYetCommencedAnnualUndiscountedAmount_57d44576-c91e-49c7-8ad6-bb0f08ca196b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_2b4fec8f-67e1-49f4-be56-6ee35076d31f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfOperatingLeasedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_0f396672-e7b6-4e99-af98-b2b26c110dfb" xlink:to="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_2b4fec8f-67e1-49f4-be56-6ee35076d31f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_2b4fec8f-67e1-49f4-be56-6ee35076d31f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b3f2c1da-ac38-4f39-b146-cdbc76d75e64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_e6ff18ac-b1bf-4ee2-b1a7-a32042237e4b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b3f2c1da-ac38-4f39-b146-cdbc76d75e64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoAndSanDiegoCaliforniaAustinTexasMarseilleFranceAndRichmondVirginiaMember_3a89b5b2-90aa-4b22-a62c-904a6782c21d" xlink:href="vcyt-20220630.xsd#vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoAndSanDiegoCaliforniaAustinTexasMarseilleFranceAndRichmondVirginiaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b3f2c1da-ac38-4f39-b146-cdbc76d75e64" xlink:to="loc_vcyt_HeadquartersAndLaboratoryFacilitiesSouthSanFranciscoAndSanDiegoCaliforniaAustinTexasMarseilleFranceAndRichmondVirginiaMember_3a89b5b2-90aa-4b22-a62c-904a6782c21d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_FacilitiesInMarseilleFranceMember_30329179-d367-4241-a325-166abcad96fd" xlink:href="vcyt-20220630.xsd#vcyt_FacilitiesInMarseilleFranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b3f2c1da-ac38-4f39-b146-cdbc76d75e64" xlink:to="loc_vcyt_FacilitiesInMarseilleFranceMember_30329179-d367-4241-a325-166abcad96fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_968fb2f4-9291-4291-9fa6-cc9d3cf21b40" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_2b4fec8f-67e1-49f4-be56-6ee35076d31f" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_968fb2f4-9291-4291-9fa6-cc9d3cf21b40" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_968fb2f4-9291-4291-9fa6-cc9d3cf21b40_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_968fb2f4-9291-4291-9fa6-cc9d3cf21b40" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_968fb2f4-9291-4291-9fa6-cc9d3cf21b40_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8fb67ec7-438d-4fd0-b240-460f64e29b09" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_968fb2f4-9291-4291-9fa6-cc9d3cf21b40" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8fb67ec7-438d-4fd0-b240-460f64e29b09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DecipherBiosciencesMember_38b61301-b161-4138-80c8-2c24bcb33664" xlink:href="vcyt-20220630.xsd#vcyt_DecipherBiosciencesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8fb67ec7-438d-4fd0-b240-460f64e29b09" xlink:to="loc_vcyt_DecipherBiosciencesMember_38b61301-b161-4138-80c8-2c24bcb33664" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3a20099b-5e3f-4bc2-ae40-2d2975856dcc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_2b4fec8f-67e1-49f4-be56-6ee35076d31f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3a20099b-5e3f-4bc2-ae40-2d2975856dcc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3a20099b-5e3f-4bc2-ae40-2d2975856dcc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3a20099b-5e3f-4bc2-ae40-2d2975856dcc" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3a20099b-5e3f-4bc2-ae40-2d2975856dcc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_73642a04-8074-456a-91d1-e37649917224" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3a20099b-5e3f-4bc2-ae40-2d2975856dcc" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_73642a04-8074-456a-91d1-e37649917224" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffMarketFavorableLeaseMember_a79298a5-85dd-4c34-97be-0ec7f4e337a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OffMarketFavorableLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_73642a04-8074-456a-91d1-e37649917224" xlink:to="loc_us-gaap_OffMarketFavorableLeaseMember_a79298a5-85dd-4c34-97be-0ec7f4e337a2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/DebtNarrativeDetails" xlink:type="extended" id="id98e0063b39d4c3b8a6a9148e01f2dc8_DebtNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_35d3bc3f-8a32-461e-9dc5-5e02eb1f98b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_35d3bc3f-8a32-461e-9dc5-5e02eb1f98b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_a710619a-0d32-4ffb-94df-e273abcdf493" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_a710619a-0d32-4ffb-94df-e273abcdf493" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_da183591-c5a4-46c7-a09b-14c1434e014c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_da183591-c5a4-46c7-a09b-14c1434e014c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtInstrumentPrepaymentPremium_56c0ff38-d8cc-42b6-88ee-7c2a8f14cbf7" xlink:href="vcyt-20220630.xsd#vcyt_DebtInstrumentPrepaymentPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_vcyt_DebtInstrumentPrepaymentPremium_56c0ff38-d8cc-42b6-88ee-7c2a8f14cbf7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_d41562de-9272-4185-9545-62763cfa0ca1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_d41562de-9272-4185-9545-62763cfa0ca1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtInstrumentEarlyTerminationFeePercentageDebtFaceAmount_5f927850-de82-4ef1-9625-0d925ef7f0e5" xlink:href="vcyt-20220630.xsd#vcyt_DebtInstrumentEarlyTerminationFeePercentageDebtFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_vcyt_DebtInstrumentEarlyTerminationFeePercentageDebtFaceAmount_5f927850-de82-4ef1-9625-0d925ef7f0e5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtInstrumentEarlyTerminationFee_876d3ed0-85b7-47e3-9470-af4247ad34b0" xlink:href="vcyt-20220630.xsd#vcyt_DebtInstrumentEarlyTerminationFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_vcyt_DebtInstrumentEarlyTerminationFee_876d3ed0-85b7-47e3-9470-af4247ad34b0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid_f1bb6b48-0a30-4b72-8f24-5b891b16045d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid_f1bb6b48-0a30-4b72-8f24-5b891b16045d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_7de9011d-48e5-44e6-ae4c-094fe8f06342" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_LongTermDebt_7de9011d-48e5-44e6-ae4c-094fe8f06342" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b3d8868d-576e-4413-8936-726816593dbb" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e6ef411b-46b3-430d-b654-30bce4cd007d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e6ef411b-46b3-430d-b654-30bce4cd007d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e6ef411b-46b3-430d-b654-30bce4cd007d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e6ef411b-46b3-430d-b654-30bce4cd007d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e6ef411b-46b3-430d-b654-30bce4cd007d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1a74ab17-6d16-4942-8470-b12beb8fd91b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e6ef411b-46b3-430d-b654-30bce4cd007d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1a74ab17-6d16-4942-8470-b12beb8fd91b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_d652678d-286c-42f6-9d95-3b1624446a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1a74ab17-6d16-4942-8470-b12beb8fd91b" xlink:to="loc_us-gaap_LineOfCreditMember_d652678d-286c-42f6-9d95-3b1624446a5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_TermLoanAdvanceMember_b948dc74-c152-489c-be46-a53766071b79" xlink:href="vcyt-20220630.xsd#vcyt_TermLoanAdvanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1a74ab17-6d16-4942-8470-b12beb8fd91b" xlink:to="loc_vcyt_TermLoanAdvanceMember_b948dc74-c152-489c-be46-a53766071b79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_278f1e18-af0b-43a1-93f2-5299c5ad6e21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_278f1e18-af0b-43a1-93f2-5299c5ad6e21" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_278f1e18-af0b-43a1-93f2-5299c5ad6e21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_278f1e18-af0b-43a1-93f2-5299c5ad6e21" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_278f1e18-af0b-43a1-93f2-5299c5ad6e21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_1a927c3b-28f5-4aae-b86b-e7c7b7f664c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_278f1e18-af0b-43a1-93f2-5299c5ad6e21" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_1a927c3b-28f5-4aae-b86b-e7c7b7f664c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_SiliconValleyBankMember_219170ca-1914-4ea5-bb3c-7854ac33d79f" xlink:href="vcyt-20220630.xsd#vcyt_SiliconValleyBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_1a927c3b-28f5-4aae-b86b-e7c7b7f664c9" xlink:to="loc_vcyt_SiliconValleyBankMember_219170ca-1914-4ea5-bb3c-7854ac33d79f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_3596c544-bf0f-4a80-9819-97e84cb02095" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_us-gaap_CreditFacilityAxis_3596c544-bf0f-4a80-9819-97e84cb02095" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_3596c544-bf0f-4a80-9819-97e84cb02095_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_3596c544-bf0f-4a80-9819-97e84cb02095" xlink:to="loc_us-gaap_CreditFacilityDomain_3596c544-bf0f-4a80-9819-97e84cb02095_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_0bd040bf-cd8a-4e12-a5cd-ba3491ca5b28" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_3596c544-bf0f-4a80-9819-97e84cb02095" xlink:to="loc_us-gaap_CreditFacilityDomain_0bd040bf-cd8a-4e12-a5cd-ba3491ca5b28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_44dcacca-9c27-4634-b2c6-ad0011662339" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_0bd040bf-cd8a-4e12-a5cd-ba3491ca5b28" xlink:to="loc_us-gaap_SecuredDebtMember_44dcacca-9c27-4634-b2c6-ad0011662339" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_8ebc5d55-db97-45b5-b1cc-b464fc7b3be9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_0bd040bf-cd8a-4e12-a5cd-ba3491ca5b28" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_8ebc5d55-db97-45b5-b1cc-b464fc7b3be9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_cf865ea9-8923-41bb-b535-79c8646af382" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_us-gaap_VariableRateAxis_cf865ea9-8923-41bb-b535-79c8646af382" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_cf865ea9-8923-41bb-b535-79c8646af382_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_cf865ea9-8923-41bb-b535-79c8646af382" xlink:to="loc_us-gaap_VariableRateDomain_cf865ea9-8923-41bb-b535-79c8646af382_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_34800bce-b343-4887-a581-62ec82201bef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_cf865ea9-8923-41bb-b535-79c8646af382" xlink:to="loc_us-gaap_VariableRateDomain_34800bce-b343-4887-a581-62ec82201bef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_a825f7da-945b-4f7d-8c4c-760d34cabbd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_34800bce-b343-4887-a581-62ec82201bef" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_a825f7da-945b-4f7d-8c4c-760d34cabbd7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ba609270-ef62-46bf-8859-a0edbe371d9e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_srt_RangeAxis_ba609270-ef62-46bf-8859-a0edbe371d9e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ba609270-ef62-46bf-8859-a0edbe371d9e_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ba609270-ef62-46bf-8859-a0edbe371d9e" xlink:to="loc_srt_RangeMember_ba609270-ef62-46bf-8859-a0edbe371d9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ceb5c0c0-41a5-4398-8919-0f0f83dfa3a1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ba609270-ef62-46bf-8859-a0edbe371d9e" xlink:to="loc_srt_RangeMember_ceb5c0c0-41a5-4398-8919-0f0f83dfa3a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_087e727c-a2b0-4c37-9421-64079035f953" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ceb5c0c0-41a5-4398-8919-0f0f83dfa3a1" xlink:to="loc_srt_MinimumMember_087e727c-a2b0-4c37-9421-64079035f953" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtPrepaymentTrancheAxis_890d5fa9-8542-454b-8133-9e634bcf9258" xlink:href="vcyt-20220630.xsd#vcyt_DebtPrepaymentTrancheAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_ef6b26c8-0da7-4aaa-a880-e02e4efb060b" xlink:to="loc_vcyt_DebtPrepaymentTrancheAxis_890d5fa9-8542-454b-8133-9e634bcf9258" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtPaymentTrancheDomain_890d5fa9-8542-454b-8133-9e634bcf9258_default" xlink:href="vcyt-20220630.xsd#vcyt_DebtPaymentTrancheDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_vcyt_DebtPrepaymentTrancheAxis_890d5fa9-8542-454b-8133-9e634bcf9258" xlink:to="loc_vcyt_DebtPaymentTrancheDomain_890d5fa9-8542-454b-8133-9e634bcf9258_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtPaymentTrancheDomain_3ea29738-1bc5-40ef-ad47-39cefc4dd429" xlink:href="vcyt-20220630.xsd#vcyt_DebtPaymentTrancheDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_vcyt_DebtPrepaymentTrancheAxis_890d5fa9-8542-454b-8133-9e634bcf9258" xlink:to="loc_vcyt_DebtPaymentTrancheDomain_3ea29738-1bc5-40ef-ad47-39cefc4dd429" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtPrepaymentTrancheThreeMember_03ac2364-a1dd-45b0-8009-24fc6490058d" xlink:href="vcyt-20220630.xsd#vcyt_DebtPrepaymentTrancheThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_vcyt_DebtPaymentTrancheDomain_3ea29738-1bc5-40ef-ad47-39cefc4dd429" xlink:to="loc_vcyt_DebtPrepaymentTrancheThreeMember_03ac2364-a1dd-45b0-8009-24fc6490058d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/DebtScheduleofLoanandSecurityAgreementDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#DebtScheduleofLoanandSecurityAgreementDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/DebtScheduleofLoanandSecurityAgreementDetails" xlink:type="extended" id="ie1945512553e482db15d7cd4ccd5b1a8_DebtScheduleofLoanandSecurityAgreementDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_c1e448fa-6bb3-4082-938d-d8fa51796d66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_0552b332-4985-4539-96b2-9ee0e54b1e94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c1e448fa-6bb3-4082-938d-d8fa51796d66" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_0552b332-4985-4539-96b2-9ee0e54b1e94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_DebtInstrumentEndOfTermPaymentInterestAmount_8087e45e-51ac-49c8-8e2f-7218ff341f87" xlink:href="vcyt-20220630.xsd#vcyt_DebtInstrumentEndOfTermPaymentInterestAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c1e448fa-6bb3-4082-938d-d8fa51796d66" xlink:to="loc_vcyt_DebtInstrumentEndOfTermPaymentInterestAmount_8087e45e-51ac-49c8-8e2f-7218ff341f87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_03d2e7c5-ad30-4528-8eb2-db41017e5985" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c1e448fa-6bb3-4082-938d-d8fa51796d66" xlink:to="loc_us-gaap_LongTermDebt_03d2e7c5-ad30-4528-8eb2-db41017e5985" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_caff9bc4-3d7f-4b67-a135-7945a2106cd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c1e448fa-6bb3-4082-938d-d8fa51796d66" xlink:to="loc_us-gaap_DebtInstrumentTable_caff9bc4-3d7f-4b67-a135-7945a2106cd5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caff9bc4-3d7f-4b67-a135-7945a2106cd5" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_898a14e7-0fb9-4699-bd85-76a2bebb6ef2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_0ecc36e6-d3eb-4341-a797-a77fe8ee7a3c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_898a14e7-0fb9-4699-bd85-76a2bebb6ef2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_5a9b7a3d-a3f7-4eea-8c58-eda111336de9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_898a14e7-0fb9-4699-bd85-76a2bebb6ef2" xlink:to="loc_us-gaap_LineOfCreditMember_5a9b7a3d-a3f7-4eea-8c58-eda111336de9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_124639d6-d2df-4877-8419-0f27404266fd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caff9bc4-3d7f-4b67-a135-7945a2106cd5" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_124639d6-d2df-4877-8419-0f27404266fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_124639d6-d2df-4877-8419-0f27404266fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_124639d6-d2df-4877-8419-0f27404266fd" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_124639d6-d2df-4877-8419-0f27404266fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_2fef6920-2f9a-481d-8767-fb06aa832d57" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_124639d6-d2df-4877-8419-0f27404266fd" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_2fef6920-2f9a-481d-8767-fb06aa832d57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_SiliconValleyBankMember_ac24aba7-6005-4817-bcaa-f88ca6aedf87" xlink:href="vcyt-20220630.xsd#vcyt_SiliconValleyBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_2fef6920-2f9a-481d-8767-fb06aa832d57" xlink:to="loc_vcyt_SiliconValleyBankMember_ac24aba7-6005-4817-bcaa-f88ca6aedf87" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.veracyte.com/role/StockholdersEquityDetails" xlink:type="simple" xlink:href="vcyt-20220630.xsd#StockholdersEquityDetails"/>
  <link:definitionLink xlink:role="http://www.veracyte.com/role/StockholdersEquityDetails" xlink:type="extended" id="i79d970b0d9cd47da9f4eae72cc13b021_StockholdersEquityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_229e91e0-498f-4850-ac30-4e6ba501b156" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_16327431-e76c-4001-b48c-5526bb7d7fce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_229e91e0-498f-4850-ac30-4e6ba501b156" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_16327431-e76c-4001-b48c-5526bb7d7fce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_771224bb-2667-41b9-acf9-d5da98a6fc00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_229e91e0-498f-4850-ac30-4e6ba501b156" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_771224bb-2667-41b9-acf9-d5da98a6fc00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_b23fd2c4-d8f0-4723-91a4-4dd80c2dbcd6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_229e91e0-498f-4850-ac30-4e6ba501b156" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_b23fd2c4-d8f0-4723-91a4-4dd80c2dbcd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_03ec7d15-dffe-4a50-91c1-d34fa10bd85b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_229e91e0-498f-4850-ac30-4e6ba501b156" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_03ec7d15-dffe-4a50-91c1-d34fa10bd85b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_d9832cf4-7d48-4e86-97d0-89e41a34aee3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_03ec7d15-dffe-4a50-91c1-d34fa10bd85b" xlink:to="loc_us-gaap_AwardTypeAxis_d9832cf4-7d48-4e86-97d0-89e41a34aee3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9832cf4-7d48-4e86-97d0-89e41a34aee3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_d9832cf4-7d48-4e86-97d0-89e41a34aee3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9832cf4-7d48-4e86-97d0-89e41a34aee3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_783bc25d-cee8-4daa-a7d2-e624e7fcea2a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_d9832cf4-7d48-4e86-97d0-89e41a34aee3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_783bc25d-cee8-4daa-a7d2-e624e7fcea2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcyt_EmployeeAndNonEmployeeStockOptionMember_6c131e72-dfee-445d-bd71-addac91cadbd" xlink:href="vcyt-20220630.xsd#vcyt_EmployeeAndNonEmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_783bc25d-cee8-4daa-a7d2-e624e7fcea2a" xlink:to="loc_vcyt_EmployeeAndNonEmployeeStockOptionMember_6c131e72-dfee-445d-bd71-addac91cadbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_d4d11660-e98b-425b-ab17-eb44933dd40c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_783bc25d-cee8-4daa-a7d2-e624e7fcea2a" xlink:to="loc_us-gaap_EmployeeStockMember_d4d11660-e98b-425b-ab17-eb44933dd40c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-roles-2022.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
