血脂分析测试的国家指南

NationalGuidelinesonLipidProfileTesting

Dr.Sheng-kaiYan,PhDDepartmentofLaboratoryMedicine,PekingUnionMedicalCollegeHospitalProfessorzhouxinDepartmentofLaboratoryMedicine,Zhongnanhospitalofwuhanuniversity.Preface

Bloodlipid

analysishasasubstantialimportancetowardsthepreventionandmanagementofatherosclerosisandcoronaryheartdisease(CHD).Itisalsobeingwidelyappliedtothestudiesofmanyotherrelatedclinicalconditions,suchasdiabetesmellitus,kidneydiseases,andmetabolicdisordersinpostmenopausalwomen.Recently,theLipidExpertPaneloftheChineseSocietyofLaboratoryMedicine(CSLM)oftheChineseMedicalAssociation(CMA)hascomeupwiththepracticalguidelinesandrecommendationsonlipidprofiletesting.lipidprofiletesting:totalcholesterol(TC)triglycerides(TG)highdensitylipoprotein–cholesterol(HDL-C)lowdensitylipoprotein-cholesterol(LDL-C)apolipoproteinA1(ApoA1)apolipoproteinB(ApoB)lipoprotein(a)[Lp(a)]TheGuidelinesincludethecontentasfollows,PrefacePreanalyticalfactorsaffectinglipidtestresultsMethodsoflipidanalysisReagentselectioncriteriaandpracticalguidelinesClinicalsignificanceofcutoffvaluesintheinterpretationoflipidprofileresultsSee:ChinJLabMed,2003,26(3):182~184中华检验医学杂志,2003,26(3):182-184PreanalyticalFactorsAffectingLipidTestResultsAsubject’slipidprofileshouldbemeasuredwhentheindividualisinasteadymetabolicstate.Subjectsshouldmaintaintheirusualdietandweightforatleast2weekspriortothemeasurementoftheirlipidsorlipoproteins.Subjectsshouldnotperformvigorousphysicalactivityduringthe24hourspriortotesting.

RecommendationsforminimizingpreanalyticalvariationMultiplemeasurementsshouldbeperformedwhthin2months,atleastoneweekapart,beforemakingamedicaldecisionaboutfurtheraction.Fastingornon-fastingspecimenscanbeusedforTCtesting.However,a12-hfastingspecimenisrequiredforTGandrecommendedforlipoproteins.Thesubjectshouldbeseatedforatleast5minutesbeforespecimencollection.Thetourniquetshouldnotbekeptonmorethanoneminuteduringvenipuncture.

SuggestionstoreducethepreanalyticalvariationsonbloodlipidprofiletestingBothserumandplasmaaresuitableforanalysis.Serumismorecommonandconvenient.TheresultobtainedfromEDTAplasmashouldbecorrectedforthedilutioneffectbyafactorof1.03.Theseparatedserumshouldbeprocessedassoonaspossible.Samplesthatcouldnotbeanalyzedwithin24hours,canbestoredat4℃foroneweekorat-20℃forseveralmonthsandat-70℃foratleasthalfayear.Repeatedfreezeandthawshouldbeavoided.

SuggestionstoreducethepreanalyticalvariationsonbloodlipidprofiletestingMethodsofLipidAnalysis

AnalyticalMethodsForroutinelipidanalysisSerumTC:

Enzymaticmethod(CHOD-PAPmethod)SerumTG:

Enzymaticmethod(GPO-PAPmethod)

SerumHDL-C:

Homogeneousmethods

SerumLDL-C:

Homogeneousmethods

SerumApoA1/ApoBandLp(a):

Immunoturbidimetry(ITA)methodImmunonephelometry(INA)method(ThefirstchoicewouldbeITA,followedbyINA)SerumHDL-C

—Homogeneousmethods

Clearancemethod

Syntheticpolymer/detergentHDL-Cassay,SPD

DaiichiPureChemicalsCo.

CatalaseHDL-Cassay,CAT

DenkaSeikenRandoxCo.ReferenceDiagnostics

PolymedcoSerumHDL-C

—Homogeneousmethods

PEG-modifiedenzymeHDL-Cassay，PEGMEKyowaMedexCo.RocheDiagnosticsCentronicGmbHImmunoseparationmethod,IS

InternationalReagentsCorpHDL-Cassay，IRCInternationalReagentsCo./Sysmex

AntibodyimmunoseparationHDL-Cassay，ABWakoPureChemicalsIndustrySerumHDL-C

—

Homogeneousmethods

PolyanionPolymer/detergentHDL-Cassay，PPD

DaiichiPureChemicalsCo.GenzymeDiagnosticsSerumHDL-C

—

Homogeneousmethods

ClearancemethodSurfactantLDL-Cassay，SUR

DaiichiPureChemicalsCo.GenzymeDiagnostics

CatalaseLDL-Cassay，CAT

DenkaSeiken

RANDOX

Polymedco

KyowaMedex

RocheSerumLDL-C

—Homogeneousmethod

ProtectingreagentLDL-Cassay，PRO

WakoChemicals

SigmaDiagnosticsCalixareneLDL-Cassay，CALInternationalReagentsCo./Sysmex

SolubilizationLDL-Cassay，SOLSerumLDL-C

—Homogeneousmethod

SerumLp(a)

—Immunoturbidimetry/immunonephelometry

Thereagentshouldpreferablybepolyclonalormixedmonoclonalantibodies,thatcouldrecognizedifferentepitopesoftheApo(a)molecule.ITAismorepreferablethanINA.Spectrophotometersandsemi-/automaticbiochemicalanalyzerswouldbesuitableforanalysisonceverifiedforproperfunctioning.Allsamplers,dilutors,pipettesandmicropipettesmustbecalibrated.Automaticbiochemicalanalyzers(fullyorsemi-automatic)arerecommendedforuseinbloodlipidtesting.RequirementsonAnalyticalInstruments

Parametersshouldbesetaccordingtothemanufacturers’instructionsandassignedcalibratorvaluesonthepackageinsert.

Theparametersshouldnotbeliberallychanged.SettingtheParametersLaboratoriesshoulduseaccreditedqualitycontrol(QC)materialswithserummatrixastheinternalqualitycontrol.TheQCmaterialsshouldcoverboththenormalandpathologicalranges.ThereareQCmaterialsspecificallydesignedforlipidanalysisthatlaboratoriescouldconsidertopurchase.QualityControlWhilechoosingindividualQCmaterials,oneshouldconsidercarefullythedynamicrangeandthetargetvaluesforthecorrespondinganalyticalmethods.Aparallelrunshouldbeperformedforanoverlappingperiodwithboththecurrentandnewlotcontrolmaterials.EnrolmenttoexternalqualityassessmentprogramsisaMUST.QualityControlReagentSelectionCriteriaandPracticalGuidelines

InaccuracyandImprecision

Inaccuracy(Bias)Imprecision(CV)Totalerrors*

TC≤±3%≤3%8.9%TG≤±5%≤5%≤15%HDL-C≤±5%≤4%≤13%LDL-C≤±4%≤4%≤12%ApoAI≤±3%≤±5%ApoB≤±3%≤±5%Lp(a)≤±4%

≤±10%

*Totalerrors=Bias%+1.96CVAnalyticalSensitivityWhenphenolisemployedinenzymaticanalysisofserumTC,theabsorbanceofTC=5.2mmol/Lat500nm(A500nm)isabout0.30-0.35.Therefore,A500nmof0.005shouldgive0.08mmol/LTC.ThesensitivityofTGenzymaticanalysisshouldbeA500nm

≥0.2atTG2mmol/L.AnalyticalSensitivityInusinghomogeneousassaysforHDL-CandLDL-C,theminimalmeasurablelevelshouldbe0.01mmol/L.ThelowestdetectionlimitsforserumApoA1andApoBbyimmunoturbidimetryorimmunonephelometryshouldbe0.5g/L,andthatforLp(a)shouldbe5mg/L.LinearityTheupperlimitoflinearityis13mmol/Lwhenusingthedilutionratioof1:100inenzymaticanalysisofTC.Itwilllowertheupperlimitifsmallerdilutionratiosareused.ThelinearityoftheenzymaticTGassayshouldatleastbe11.3mmol/L(1000mg/dL).ThelinearityofhomogeneousassaysforHDL-CandLDL-Cshouldatleastbe2.59mmol/Land7.77mmol/Lrespectively.LinearityThelinearityofserumApoA1andApoBbyITAorINAshouldnotbelessthan2.0g/LandthatofLp(a)notlessthan800mg/L,respectively.

SpecificityInenzymaticanalysisofserumTC,thecolorreactionissubjecttocertaindegreeofspectralinterferencesfromvariousnon-cholesterolsterols.Normally,thereisonlynegligibleamount(about1%)ofthesenon-cholesterolsterolsintheblood.InenzymaticanalysisofTG,thelipoproteinlipase(LPL)canhydrolyzeTGandalsomono-glyceridesanddi-glycerides.Thelattertwoconstituteabout3%oftotalTGmeasured.SpecificityTherecoveriesinhomogeneousassaysofHDL-CandLDL-C,immunoturbidimetryofserumApoAI,ApoBandLp(a)shouldpreferablebeintherangeof90%-110%.Ingeneral,themeasurementsshouldnotbeaffectedbyotherlipoproteins.Thereisnosignificantinterferenceuptohemoglobinconcentrationof2g/L,bilirubinconcentrationof0.1g/LinenzymaticanalysisofserumTC.InterferenceinenzymaticanalysisofTGissimilartothatoftheTCassay.Therewillbenegativeinterferencewhenbilirubin>100mol/Lorascorbicacid>170mol/L.Hemoglobinwillcausespectralinterferences.Grosslyhemolysedsamplesarenotsuitableforanalysis.InterferencesThereisnosignificantinterferenceofTG<5.65mmol/L(500mg/dl),bilirubin<513mol/L(30mg/dl),andHb<5g/LinmosthomogeneousassaysforHDL-CandLDL-C,aswellastheimmunoturbidimetricorimmunonephelomentricassaysforserumApoA1,ApoBandLp(a).InterferencesReagentStabilityLyophilizedreagentscanusuallybestoredatleastfor1yearifkeptunopenedat2℃~8℃.ReconstitutedcholesterolandTGenzymaticreagentsshouldbestoredat2℃~8℃for2days.Reagentsshouldbediscardedifpinkcolorisseen.Theabsorbanceat500nmofthereagentblankshouldbe≤0.05.Unopenedreagentsolutionsshouldbestableforatleast6monthsat2℃~8℃andfor1monthafterbeingopened.ReactionRates

Thereactionshouldnotbelongerthan5minand8minat37℃

forenzymaticanalysisofserumcholesterolandTGrespectively.TheendpointofimmunoturbidimetricassaysforserumApoA1,ApoBandLp(a)couldbedeterminedaccordingtotheirreactioncurvesshownintheautomaticanalyzer.Generally,reactiontimeof8~10minutesisacceptable.CalibrationTheusershouldusethecalibrationmaterialsprovidedbythemanufacturer.Thecalibrationmaterialsshouldbetraceabletothereferencemethods.Oneshouldavoidusingdifferentbrandsofcalibrationmaterialsastoensureconsist