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  <xs:element id="exdx_StockIssuedDuringPeriodValueWarrantsExercisedNet" abstract="false" name="StockIssuedDuringPeriodValueWarrantsExercisedNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_IssuanceOfStockFromVestedRestrictedStockUnitsAndPaymentOfEmployeesTaxesShares" abstract="false" name="IssuanceOfStockFromVestedRestrictedStockUnitsAndPaymentOfEmployeesTaxesShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_AmortizationOfLoanCommitmentFees" abstract="false" name="AmortizationOfLoanCommitmentFees" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_NonCashOperatingLeaseExpense" abstract="false" name="NonCashOperatingLeaseExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_IncreaseDecreaseInPrepaidExpenseAndCurrentOtherAssets" abstract="false" name="IncreaseDecreaseInPrepaidExpenseAndCurrentOtherAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_OtherFinancialInformationAbstract" abstract="true" name="OtherFinancialInformationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="exdx_PrepaidExpensesAndOtherCurrentAssetsPropertyPlantAndEquipmentAndAccruedLiabilitiesTextBlock" abstract="false" name="PrepaidExpensesAndOtherCurrentAssetsPropertyPlantAndEquipmentAndAccruedLiabilitiesTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="exdx_CustomerAMember" abstract="true" name="CustomerAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_CustomerBMember" abstract="true" name="CustomerBMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_CustomerCMember" abstract="true" name="CustomerCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_AVISECTDTestMember" abstract="true" name="AVISECTDTestMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_SupplierOneMember" abstract="true" name="SupplierOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_SupplierTwoMember" abstract="true" name="SupplierTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_LoanCommitmentFeesCurrent" abstract="false" name="LoanCommitmentFeesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_AmortizationOfLoanCommitmentFeesNoncashExpense" abstract="false" name="AmortizationOfLoanCommitmentFeesNoncashExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_RealizedGainLossOnLoanCommitment" abstract="false" name="RealizedGainLossOnLoanCommitment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualInstallments" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualInstallments" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="exdx_CommercialMember" abstract="true" name="CommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_Government1Member" abstract="true" name="Government1Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_ClientDirectBillMember" abstract="true" name="ClientDirectBillMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PrepaidMaintenanceAndInsuranceContracts" abstract="false" name="PrepaidMaintenanceAndInsuranceContracts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_LaboratoryEquipmentMember" abstract="true" name="LaboratoryEquipmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_ComputerEquipmentAndSoftwareMember" abstract="true" name="ComputerEquipmentAndSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_FinanceLeaseRightOfUseAssetsMember" abstract="true" name="FinanceLeaseRightOfUseAssetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveTermLoanFacilityMember" abstract="true" name="PerceptiveTermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveTermLoanFacilityTrancheALoanMember" abstract="true" name="PerceptiveTermLoanFacilityTrancheALoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_AmendedLoanAgreementMember" abstract="true" name="AmendedLoanAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveTermLoanFacilityTrancheBLoanMember" abstract="true" name="PerceptiveTermLoanFacilityTrancheBLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveTermLoanFacilityTrancheCLoanMember" abstract="true" name="PerceptiveTermLoanFacilityTrancheCLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveTermLoanFacilityTrancheDLoanMember" abstract="true" name="PerceptiveTermLoanFacilityTrancheDLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_A2017TermLoanMember" abstract="true" name="A2017TermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_EquipmentNotesPayableMember" abstract="true" name="EquipmentNotesPayableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_PerceptiveCreditHoldingsIVLPMember" abstract="true" name="PerceptiveCreditHoldingsIVLPMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_InnovatusLifeSciencesLendingFundMember" abstract="true" name="InnovatusLifeSciencesLendingFundMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_CreditAgreementAndTrancheAWarrantsMember" abstract="true" name="CreditAgreementAndTrancheAWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_TrancheAWarrantSharesMember" abstract="true" name="TrancheAWarrantSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_CreditAgreementWarrantsMember" abstract="true" name="CreditAgreementWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_DebtInstrumentNumberOfTranches" abstract="false" name="DebtInstrumentNumberOfTranches" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="exdx_LineOfCreditFacilityAccordionFeatureIncreaseLimit" abstract="false" name="LineOfCreditFacilityAccordionFeatureIncreaseLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_DebtInstrumentInterestRateDebtPrepaymentPercentage" abstract="false" name="DebtInstrumentInterestRateDebtPrepaymentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="exdx_LineOfCreditFacilityCovenantMinimumUnrestrictedCashBalance" abstract="false" name="LineOfCreditFacilityCovenantMinimumUnrestrictedCashBalance" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightVestedAndExercisable" abstract="false" name="ClassOfWarrantOrRightVestedAndExercisable" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightExercised" abstract="false" name="ClassOfWarrantOrRightExercised" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_StockIssuedDuringPeriodSharesWarrantsExercised" abstract="false" name="StockIssuedDuringPeriodSharesWarrantsExercised" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_PaymentForDebtPrepaymentCost" abstract="false" name="PaymentForDebtPrepaymentCost" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightUnissuedAmount" abstract="false" name="ClassOfWarrantOrRightUnissuedAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_DebtInstrumentNumberOfPeriodicPayments" abstract="false" name="DebtInstrumentNumberOfPeriodicPayments" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="exdx_LongTermDebtIncludingUndiscountedInterest" abstract="false" name="LongTermDebtIncludingUndiscountedInterest" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_LongTermDebtUndiscountedInterestAmount" abstract="false" name="LongTermDebtUndiscountedInterestAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_LeaseTypeAxis" abstract="true" name="LeaseTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="exdx_LeaseTypeDomain" abstract="true" name="LeaseTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_EmbeddedFinanceLeaseMember" abstract="true" name="EmbeddedFinanceLeaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_RoyaltyObligationPercentageOfSales" abstract="false" name="RoyaltyObligationPercentageOfSales" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="exdx_PurchaseObligationAmendedSupplyAgreementNumberOfSuppliers" abstract="false" name="PurchaseObligationAmendedSupplyAgreementNumberOfSuppliers" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="exdx_PurchaseObligationPaidInPriorFiscalYear" abstract="false" name="PurchaseObligationPaidInPriorFiscalYear" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_FinanceLeaseFairValueOfLeasedAsset" abstract="false" name="FinanceLeaseFairValueOfLeasedAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightCancelled" abstract="false" name="ClassOfWarrantOrRightCancelled" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_WarrantLiabilityFairValueDisclosure" abstract="false" name="WarrantLiabilityFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ShelfRegistrationStatementMember" abstract="true" name="ShelfRegistrationStatementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_AtTheMarketSalesAgreementMember" abstract="true" name="AtTheMarketSalesAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_A2025PublicOfferingMember" abstract="true" name="A2025PublicOfferingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_SaleOfStockAuthorizedAmount" abstract="false" name="SaleOfStockAuthorizedAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_SaleOfStockRemainingAuthorizedAmount" abstract="false" name="SaleOfStockRemainingAuthorizedAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightIssued" abstract="false" name="ClassOfWarrantOrRightIssued" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_ExpirationApr12026Member" abstract="true" name="ExpirationApr12026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_CommonSharesAvailableForGrantUnderThe2019PlanMember" abstract="true" name="CommonSharesAvailableForGrantUnderThe2019PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_IncentiveAwardPlan2019Member" abstract="true" name="IncentiveAwardPlan2019Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorizedPercentage" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorizedPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="exdx_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseDecreaseInNumberOfSharesAuthorized" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseDecreaseInNumberOfSharesAuthorized" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_ReportableSegmentMember" abstract="true" name="ReportableSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="exdx_OutsideServicesExpense" abstract="false" name="OutsideServicesExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
