Description:ProductName:Thyroglobulin#ofSamples:1x96AssaysIntendedUse:Immunoenzymaticcolorimetricmethod(ELISA)forquantitativedeterminationofThyroglobulininhumanserum.Introduction:Thyroglobulin(Tg),aglycoproteinwithamolecularweightofabout660,000Daltons,isthethyroid’smainiodineproteinandthemostimportantcompoundoffollicularcolloid.ThyroglobulinistheformunderwhichtheactivehormonesT3andT4togetherwiththeirimmediateforerunnersMITandDITarelaidinsidethethyroidgland.TheclinicalapplicationsofthehTgdosageseemtooriginatefromitsspecificityforthethyroidandrelatedcells.ThedosageofhTgcanbeusedassupporttoscintigraphiesorothertechniquesforstudyingpathogenesis,makingadiagnosisandanalyzingthecourseofthyroiddisorders.ThedosageofTgbeforeandafterreplacementtreatmentwithL-Thyroxincannotbeestablishedincasesofhypothyroidismduetothyroidagenesis.Incasesofsecondaryhypothyroidismwithadysglandulargoiterorectopicthyroid,thelevelsofhTgarenormalorhigh.ThecirculatinglevelsofhTgtendtoincreaseinseveralthyroiddisorderssuchastoxicandatoxicgoiter,subacutethyroiditis,Basedow’sdiseaseandcarcinoma.InBasedow’sdiseasethehTgdosageisapotentiallyinterestingindexofnormalizationofhyperthyroidisminpatientstreatedwithanti-thyroiddrugs.Intheoncologyfieldandmorespecificallyfordifferentiatedthyroidcarcinoma,thereareverypromisingapplicationslinkedtotheABIlityofthyroidtumorstissuestoconcentrateiodineandsynthesizehTgasanormalthyroid.BasicallythedosageofhTgcanbeusedasfollows:Pre-operatingdiagnosisofthyroidtumors.ThisapplicationdoesnotallowthedifferentiateddiagnosisofthetumorasthevaluesofhTgseeninmalignantandbenignnodulesaresuperimposable.Post-operationmonitoringInpatientstreatedsurgicallyorwithrADIotherapy,longlastinghTglevelssuggestthepresenceofaresidualcarcinomaand/orcarcinomawithmetastasis.MonitoringoftotallythyroidectomizedpatientsTheuseofcirculatinghTgasanindicatorofrecurrenttumors(metastasisMarker)hasanestablishedclinicalvalue:theincreaseofThyroglobulinaemiaindicatestheneedtoundergofurtheranalysisforconfirmingthediagnosis.Interestingadvantagescancomefrom:a)areduceduseofscintigraphicdiagnostictechniquesastheyimplyregularsUSPensionofreplacementtreatmentandfrequentexposuretoradiation,b)andcompletecompletionoftheinformationobtainedviascintigraphy.Principlesoftheassay:Fourdifferentanti-Thyroglobulinmonoclonalantibodiesareused.Threeantibodiesarecoatedonthewells;thefourthissolubleandconjugatedtoBiotin.Thyroglobulininsamplesandstandardsbindstotheimmobilisedantibodiesonthesurfaceofthemicrotiterwellsandthesecond,solubleanti-Thyroglobulinantibodyconjugatedwithbiotinbindstotheimmobileantibody-Thyroglobulin-complexduringthefirstincubation.AfterawashingstepStreptavidinconjugatedwithhorseradishperoxidase(HRP)isaddedtoallwellsandreactswiththebiotinylatedantibodies.Asecondwashingstepisperformed.ThentheimmunecomplexisvisualizedbyaddingTetramethylbenzidine(TMB)substrate,whichgivesabluereactionproduct.TheintensityofthisproductisproportionaltotheamountofThyroglobulininsamplesandstandards.Sulphuricacidisaddedtostopthereaction.Thisproducesayellowendpointcolour.Absorptionat450and405nmisreadusinganELISAmicrowellplatereader.StorageandStability:Thereagentsarestableuptotheexpirydatestatedonthelabelwhenstoredat2...8°C.Afteropeningreagentsarestablefor60dayswhenstoredat2…8°C.LimitationsoftheTest:Bacterialcontaminationorrepeatedfreeze-thawcyclesofthespecimenmayaffecttheabsorbancevalues.Theresultsoftheassaymustbecarefullyinterpretedandconfirmedbyclinicalevaluationsandfurtherdiagnostictests.ReferencesRuiz-GarciaJ.,RuizdeAlmodóvarJ.M.,OleaN.andPedrazaV.(1991)J.NuclearMedicine32(3),395-398.PaciniF.,PincheraA.,GianiC.,GrassoL.,DoveriF.andBaschieriL.(1980)J.Endocrinol.Invest.3,283-292.RubelloD.,GirelliM.E.,CasaraD.,PiccoloM.,PerinA.andBusnardoB.(1990)J.Endocrinol.Invest.13,737-742.SheppardM.C.(1986)J.Medicine.NewSeries59(229),429-433.TourniaireJ.,BernardM.H.,AyzacL.,NicolasM.H.andBornetH.(1990)LaPresseMédicale19(28),1309-1312.PaciniF.,EliseiR.,FugazzolaL.andPincheraA.(1991)Diagn.Oncol.1,194-196.MassartC.andMaugendreD.(2002)Clin.Chem.48(1),108-107.AdditionalInformation:NameThyroglobulinRelatedProductNamesThyroglobulinStorageThereagentsarestableuptotheexpirydatestatedonthelabelwhenstoredat2...8°C.Afteropeningreagentsarestablefor60dayswhenstoredat2…8°C.IntendedUseResearchUseOnly