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  <xs:element id="exdx_AdjustmentsToAdditionalPaidInCapitalTemporaryEquityDeemedDividends" abstract="false" name="AdjustmentsToAdditionalPaidInCapitalTemporaryEquityDeemedDividends" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_PrepaidExpensesAndOtherCurrentAssetsPropertyPlantAndEquipmentAndAccruedLiabilitiesTextBlock" abstract="false" name="PrepaidExpensesAndOtherCurrentAssetsPropertyPlantAndEquipmentAndAccruedLiabilitiesTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="exdx_PreferredStockWarrantLiability" abstract="false" name="PreferredStockWarrantLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_AdvancePayment" abstract="false" name="AdvancePayment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_ReclassificationOfTemporaryEquityAndLiabilitiesToPermanentEquity" abstract="false" name="ReclassificationOfTemporaryEquityAndLiabilitiesToPermanentEquity" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_JanssenSIMPONIMember" abstract="true" name="JanssenSIMPONIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <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_JointVentureQuarterlyPromotionFee" abstract="false" name="JointVentureQuarterlyPromotionFee" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_A1261SuiteALeaseMember" abstract="true" name="A1261SuiteALeaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_ClientMember" abstract="true" name="ClientMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <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_DebtInstrumentPrepaymentPremiumPercentage" abstract="false" name="DebtInstrumentPrepaymentPremiumPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="exdx_ClassOfWarrantOrRightExercised" abstract="false" name="ClassOfWarrantOrRightExercised" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="exdx_DebtInstrumentStatedInterestRatePaidInKind" abstract="false" name="DebtInstrumentStatedInterestRatePaidInKind" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="exdx_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorizedPercentage" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorizedPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="exdx_AssetsUnderCapitalLeaseMember" abstract="true" name="AssetsUnderCapitalLeaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_CommonStockOptionGrantsIssuedAndOutstandingMember" abstract="true" name="CommonStockOptionGrantsIssuedAndOutstandingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_IncentiveAwardPlan2019Member" abstract="true" name="IncentiveAwardPlan2019Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_TemporaryEquityIssuedDuringThePeriodValueRedeemableConvertiblePreferredStock" abstract="false" name="TemporaryEquityIssuedDuringThePeriodValueRedeemableConvertiblePreferredStock" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_OperatingLeaseAnnualIncreaseInBaseRentPaymentPercent" abstract="false" name="OperatingLeaseAnnualIncreaseInBaseRentPaymentPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="exdx_SeriesDAndSeriesEPreferredStockMember" abstract="true" name="SeriesDAndSeriesEPreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_ReceivableBenchmarkMember" abstract="true" name="ReceivableBenchmarkMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="exdx_TemporaryEquityDeemedDividendsWithBeneficialConversionFeature" abstract="false" name="TemporaryEquityDeemedDividendsWithBeneficialConversionFeature" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_TemporaryEquityProceedsReceivedPriorToIssuance" abstract="false" name="TemporaryEquityProceedsReceivedPriorToIssuance" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_OperatingLeaseIncreaseDecreaseInMonthlyBaseRent" abstract="false" name="OperatingLeaseIncreaseDecreaseInMonthlyBaseRent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="exdx_RoyaltyObligationPercentageOfSales" abstract="false" name="RoyaltyObligationPercentageOfSales" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="exdx_TemporaryEquityRightsForMandatoryPurchase" abstract="false" name="TemporaryEquityRightsForMandatoryPurchase" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
</xs:schema>
