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  <element name="EffectiveIncomeTaxRateReconciliationAcquisitionCosts" id="cdna_EffectiveIncomeTaxRateReconciliationAcquisitionCosts" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EffectiveIncomeTaxRateReconciliationChangeInUnrecognizedTaxBenefits" id="cdna_EffectiveIncomeTaxRateReconciliationChangeInUnrecognizedTaxBenefits" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EffectiveIncomeTaxRateReconciliationInterestExpense" id="cdna_EffectiveIncomeTaxRateReconciliationInterestExpense" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EffectiveIncomeTaxRateReconciliationLiabilityContingentForUnconsolidatedSubsidiaryPercent" id="cdna_EffectiveIncomeTaxRateReconciliationLiabilityContingentForUnconsolidatedSubsidiaryPercent" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EffectiveIncomeTaxRateReconciliationPreferredStockWarrantRevaluation" id="cdna_EffectiveIncomeTaxRateReconciliationPreferredStockWarrantRevaluation" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EquityMethodInvestmentsAndCostMethodInvestmentsAbstract" id="cdna_EquityMethodInvestmentsAndCostMethodInvestmentsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExercisePriceRangeFourMember" id="cdna_ExercisePriceRangeFourMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExercisePriceRangeOneMember" id="cdna_ExercisePriceRangeOneMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExercisePriceRangeThreeMember" id="cdna_ExercisePriceRangeThreeMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExercisePriceRangeTwoMember" id="cdna_ExercisePriceRangeTwoMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="FairValueInputProbabilityOfAchievement" id="cdna_FairValueInputProbabilityOfAchievement" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="FairValueMeasurementsInterTransfersBetweenLevels" id="cdna_FairValueMeasurementsInterTransfersBetweenLevels" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="FairValueOfAssetsAndLiabilitiesMeasuredOnNonRecurringBasisLineItems" id="cdna_FairValueOfAssetsAndLiabilitiesMeasuredOnNonRecurringBasisLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IlluminaIncMember" id="cdna_IlluminaIncMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ImmumetrixIncMember" id="cdna_ImmumetrixIncMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ImpactOfCashFlowClassificationErrorAbstract" id="cdna_ImpactOfCashFlowClassificationErrorAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IncomeTaxesDisclosureLineItems" id="cdna_IncomeTaxesDisclosureLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IncomeTaxesDisclosureTable" id="cdna_IncomeTaxesDisclosureTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="IncomeTaxRecognitionThresholdPercentage" id="cdna_IncomeTaxRecognitionThresholdPercentage" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IncreaseDecreaseInServicerPayables" id="cdna_IncreaseDecreaseInServicerPayables" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InitialPublicOfferingDateOfCompletion" id="cdna_InitialPublicOfferingDateOfCompletion" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InitialPublicOfferingPolicyTextBlock" id="cdna_InitialPublicOfferingPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IssuanceOfCommonStockInInitialPublicOfferingShares" id="cdna_IssuanceOfCommonStockInInitialPublicOfferingShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IssuanceOfCommonStockInitialPublicOffering" id="cdna_IssuanceOfCommonStockInitialPublicOffering" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LaboratoryComputerAndOfficeEquipmentMember" id="cdna_LaboratoryComputerAndOfficeEquipmentMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LaboratoryCorpOfAmericaHoldingsMember" id="cdna_LaboratoryCorpOfAmericaHoldingsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturitiesRepayments" id="cdna_LongTermDebtMaturitiesRepayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturitiesRepaymentsInNextTwelveMonths" id="cdna_LongTermDebtMaturitiesRepaymentsInNextTwelveMonths" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturitiesRepaymentsInYearTwo" id="cdna_LongTermDebtMaturitiesRepaymentsInYearTwo" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturitiesRepaymentsOfInterest" id="cdna_LongTermDebtMaturitiesRepaymentsOfInterest" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturitiesRepaymentsOfPrincipal" id="cdna_LongTermDebtMaturitiesRepaymentsOfPrincipal" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="MaximumPeriodOfWarrantsExercisable" id="cdna_MaximumPeriodOfWarrantsExercisable" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="MedicareMember" id="cdna_MedicareMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="MinimumSharesOutstandingForVotingRights" id="cdna_MinimumSharesOutstandingForVotingRights" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NonvestedStockOptionsMember" id="cdna_NonvestedStockOptionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfCommercialTests" id="cdna_NumberOfCommercialTests" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OperatingLeasesExpirationMonthYear" id="cdna_OperatingLeasesExpirationMonthYear" type="xbrli:gYearMonthItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OperatingLossCarryforwardsExpirationYear" id="cdna_OperatingLossCarryforwardsExpirationYear" type="xbrli:gYearItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PotentialRefundablePortionOfUpfrontPayment" id="cdna_PotentialRefundablePortionOfUpfrontPayment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PreferredStockWarrantMember" id="cdna_PreferredStockWarrantMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract" id="cdna_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RoyaltyAgreementLiabilityMember" id="cdna_RoyaltyAgreementLiabilityMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RoyaltyRevenueReceivable" id="cdna_RoyaltyRevenueReceivable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SaleOfStockPursuantToExerciseOfUnderwritersOverAllotmentOption" id="cdna_SaleOfStockPursuantToExerciseOfUnderwritersOverAllotmentOption" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ScenarioOneMember" id="cdna_ScenarioOneMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ScheduleOfBalanceSheetComponentsTable" id="cdna_ScheduleOfBalanceSheetComponentsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="ScheduleOfFutureMinimumCommitmentsForCapitalAndOperatingLeasesTableTextBlock" id="cdna_ScheduleOfFutureMinimumCommitmentsForCapitalAndOperatingLeasesTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesAConvertiblePreferredStockMember" id="cdna_SeriesAConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesBConvertiblePreferredStockMember" id="cdna_SeriesBConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesCConvertiblePreferredStockMember" id="cdna_SeriesCConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesDConvertiblePreferredStockMember" id="cdna_SeriesDConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesEConvertiblePreferredStockMember" id="cdna_SeriesEConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesFConvertiblePreferredStockMember" id="cdna_SeriesFConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesGConvertiblePreferredStockMember" id="cdna_SeriesGConvertiblePreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesReservedForAvailableForIssuance" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesReservedForAvailableForIssuance" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantAssumedInAcquisition" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantAssumedInAcquisition" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExercised" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExercised" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExpired" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExpired" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeituresInPeriod" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeituresInPeriod" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedDuringPeriod" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedDuringPeriod" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAssumedFromAcquisitionsInPeriod" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAssumedFromAcquisitionsInPeriod" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingAggregateIntrinsicValue" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingAggregateIntrinsicValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingNumber" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingNumber" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingAggregateIntrinsicValue" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingAggregateIntrinsicValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingNumber" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingNumber" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingWeightedAverageRemainingContractualTerm" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedWeightedAverageExercisePrice" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedWeightedAverageExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodFairValue" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodFairValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageExercisedPriceSharesReserved" id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageExercisedPriceSharesReserved" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsSharesAssumedFromAcquisitionWeightedAverageExercisePrice" id="cdna_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsSharesAssumedFromAcquisitionWeightedAverageExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptions" id="cdna_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptions" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptionsWeightedAverageExercisePrice" id="cdna_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptionsWeightedAverageExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptionsWeightedAverageRemainingContractualTerm" id="cdna_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingAndExercisableOptionsWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockholdersEquityReverseStockSplitEffectiveDate" id="cdna_StockholdersEquityReverseStockSplitEffectiveDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockIssuedDuringPeriodSharesConversionOfPreferredStockToCommonStock" id="cdna_StockIssuedDuringPeriodSharesConversionOfPreferredStockToCommonStock" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockIssuedDuringPeriodValueConversionOfPreferredStockToCommonStock" id="cdna_StockIssuedDuringPeriodValueConversionOfPreferredStockToCommonStock" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SubordinatedConvertiblePromissoryNotesMember" id="cdna_SubordinatedConvertiblePromissoryNotesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SummaryActivityInGoldBullionLineItems" id="cdna_SummaryActivityInGoldBullionLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SummaryOfSignificantAccountingPoliciesLineItems" id="cdna_SummaryOfSignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SummaryOfSignificantAccountingPoliciesTable" id="cdna_SummaryOfSignificantAccountingPoliciesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="TaxCreditCarryForwardExpirationYear" id="cdna_TaxCreditCarryForwardExpirationYear" type="xbrli:gYearItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TemporaryEquityInitialConversionPrice" id="cdna_TemporaryEquityInitialConversionPrice" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TerminationAgreementDate" id="cdna_TerminationAgreementDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TerminationFee" id="cdna_TerminationFee" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TrancheATermLoanFacilityMember" id="cdna_TrancheATermLoanFacilityMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TrancheBTermLoanFacilityMember" id="cdna_TrancheBTermLoanFacilityMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFourteenEquityIncentivePlanMember" id="cdna_TwoThousandAndFourteenEquityIncentivePlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndTenTermLoanMember" id="cdna_TwoThousandAndTenTermLoanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandTwelveTermLoanMember" id="cdna_TwoThousandTwelveTermLoanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromPriorPeriodTaxPositions" id="cdna_UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromPriorPeriodTaxPositions" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UpfrontPaymentInCash" id="cdna_UpfrontPaymentInCash" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="WarrantPolicyTextBlock" id="cdna_WarrantPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="WarrantsDisclosureTextBlock" id="cdna_WarrantsDisclosureTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="WarrantsToPurchaseConvertiblePreferredStock" id="cdna_WarrantsToPurchaseConvertiblePreferredStock" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
</schema>