| Kitsize | 12x8 |
| Method | ELISA |
| Incubationtime | 1x2h,1x1h,1x30min. |
| Standardrange | 7,81-125pg/mL |
| Specimen/Volumes | 5µLCSF |
| Substrate/isotope | TMB450nm |
| RegulatoryStatus: | EU:CE |
Overthelast15yearsmeasuringAmyloid–beta(1–42)peptidehasgainedacceptanceasatooltoaidinthediagnosisofAlzheimer´sdisease.Yet,clinicalsensitivityandspecificityusuallyislessthan85%.ThiscanbelargelyattributedtotheGaussiandistributionofAmyloid–betaproductioninthepopulation.Itleadstofalsepositivesinthegroupof"low"Abetaproducersandtofalsenegativesinthegroupof"high"Abetaproducers.NormalizingtheAmyloid–beta(1–42)valuestothemostabundantandstablyproducedAbeta(1–40)isoformovercomesthislimitationandsignificantlyimprovesthediagnosticvaluetowellabove90%.IBLInternationalhassetitsgoaltodevelophighqualityimmunoassaysforconvenientandaccuratemeasurementofAmyloid–beta(1–40)andAmyloid–beta(1–42)inCSFforoptimalratioDeterminationascanbeseenbyexcellentcrossreactivitydataofbothassays(Table1)
| Peptide | Amyloid–beta (1–40)ELISA | Amyloid–beta (1–42)ELISA |
| Amyloid–beta(1–42) | 0,84% | 100% |
| Amyloid–beta(1–40) | 100% | 0,003% |
| Amyloid–beta(1-38) | 0,01% | 0,57% |
| Amyloid–beta(2-40) | 1,29% | 0,02% |
Tabelle1
Kreuzreaktivitäten(bestimmtnachDeshpande,SS(1996))
BothAssaysshowexcellentinter–andintra–assayCVs(Table2)andinter–lotCVs(Table3)profilesduetointernalqualitycontrolstandards.
| Amyloid–beta(1–40)ELISA | Amyloid–beta(1–42)ELISA | |||
| SampleNo. | mean | CV | mean | CV |
| [pg/mL] | [%] | [pg/mL] | [%] | |
| 1 | 4732 | 1.8 | 548 | 3.4 |
| 2 | 9937 | 2.1 | 1023 | 3.0 |
| 3 | 3080 | 4.5 | 849 | 3.0 |
| 4 | 10497 | 1.9 | 951 | 3.1 |
| 5 | 13506 | 2.8 | 1034 | 3.1 |
Table2
Intra–assayCV(n=20)
| Amyloid–beta(1–40)ELISA | Amyloid–beta(1–42)ELISA | |||
| SampleNo. | mean | CV | mean | CV |
| [pg/mL] | [%] | [pg/mL] | [%] | |
| 1 | 2418 | 5.4 | 193 | 4.5 |
| 2 | 3830 | 6.3 | 476 | 7.6 |
| 3 | 19407 | 4.1 | 661 | 6.9 |
| 4 | 13164 | 5.8 | 728 | 4.7 |
| 5 | 9405 | 2.7 | 873 | 7.4 |
Table3
Inter–lotand–operatorCV(n=10,3lots,3-4operators)
MethodcomparisonwithcommerciallyavailableAmyloid–beta(1–40)ELISA:R2=0.944
MethodcomparisonforthedetectionofAmyloid–beta(1–40)in119nativeCSFSamples
MethodcomparisonwithcommerciallyavailableAmyloid–beta(1–42)ELISA:R2=0.9492
MethodcomparisonforthedetectionofAmyloid–beta(1–42)in120nativeCSFSamples
Toclinicallyvalidatetheassaysanexternalstudywasdoneatthe"KlinikundPoliklinikfürPsychiatrieundPsychotherapie,KlinikumrechtsderIsarderTechnischenUniversitätMünchen,München,Germany"withoverall83clinicallyknownsamples.Theratioofbothassayvaluesshowshighclinicalsensitivityandspecificity
Amyloid–beta(1–42)⁄Amyloid–beta(1–40)ratiosuperiortoAmyloid–beta(1–42)alone
| Ratio:Amyloid–beta(1–42) ⁄Amyloid–beta(1–40) | |||
| AD | control | ||
| Diagnosis | AD | 39 | 1 |
| control | 4 | 39 | |
SimilarresultswereobtainedbyProf.Dr.med.PiotrLewczuk,LabforClinicalNeuRochemistryandNeurochemicalDementiaDiagnostics,UniversitätsklinikumErlangen,DepartmentofPsychiatryandPsychotherapy,Erlangen,Germany.(tobepublishedsoon)
ExcerptfromtheInstructionsforUse
In2010,thenumberofdementiapatientsworldwidewasestimatedat36million.Assuminganongoinglackofsufficientpreventiveandcurativetreatments,thisisexpectedtodoubleevery20years.Alzheimer’sDiseaseaccountsforroughly60-70%ofalldementiacases.Bothprevalenceandincidenceincreasewithage.Prevalenceisaround1%inthoseaged65-69,andmorethan30%inthoseaged90orolder.
ThedevelopmentoftheDiseaseischaracterizedbythreestages,asdefinedbytheUSNationalInstituteonAgingworkgroups.ApreclinicalstageofAlzheimer’sDisease,themildcognitiveimpairment(MCI)stageduetoAD,andthedementiastageduetoAD[9-11].Amyloidosisoccursasearlyasthepreclinicalstage.ThefirstcognitivedeficitscanmanifestthemselvesinMCIstage,whileinthedementiastagepatientsareunabletodoanyworkordailychores.
Theconcentrationofamyloid-beta(1-42)isthereforerecognizedasausefulbioMarker(incombinationwithotherbiomarkerssuchasTauandPhospho-Tau)indiagnosingAlzheimer’sDisease.Moreover,anumberofindependentstudies(forexample[3-5])showedtheratioofamyloid-beta(1-42)toamyloid-beta(1-40)tobeasuperiordiagnosticmarkerforAlzheimer’sDisease.
