ASCAIgAELISAisasolidphaseenzymeimmunoassay(ELISA)employinghighlypurifiedmannanforthequantitativedetectionofanti-Saccharomycescerevisiaeantibodies(ASCA)inhumanserum.ASCArecognizespecificallymannan,acomponentoftheoutercellwallofyeast.TheassayishighlyspecificandsensitiveforCrohn`sdisease.Crohn‘sdiseaseisoneofthetwomajorInflammatoryBowelDiseases(IBD).IBDisanumbrellaterm,thatcoversbothprimarydisorderscausinginflammationorulcerationinthesmallandlargeintestine,Crohn‘sdiseaseandulcerativecolitis.Crohn‘sdiseaseaffectsboth,thesmallbowelandthecolon,unlikeulcerativecolitiswhichisrestrictedtothecolononly.Theetiologyisnotrevealedyet,althoughageneticandinfectiousbackgroundforthediseaseisunderdiscussion.Colonoscopyandileoscopyaretheestablishedtoolsofdiagnosis,noSEROlogywasavailablesofar.ThoughCrohn‘sdiseaseandulcerativecolitisshareseveralsymptomsthecourseofthediseases,itscomplicationsanditsmanagementaredifferent,especiallywhenitcomesdowntosurgery.Consequentlythedifferentaldiagnosisofbothdiseasesiscrucialpriortotreatment.Aggravating,about5-10%ofthepatientscannotbedistinguishedclearlybyexistingavailablediagnosticmethodologiesandarereferredtoasindeterminatecolitis.ASCAhavebeenfoundtobespecificMarkersforCrohn`sdisease.Theyhavebeenreportedforthesepatientswithafrequencyof68%.Theidentificationofthetargetantigenmannan,amannose-richcarbohydrateantigenoftheoutercellwallofyeast,enabledthedetectionofASCAbyenzymeimmunoassay.Beingthefirstavailablehighlyspecificserologicalmarker,ASCAmaybecomeanimportanttoolforthedifficulttaskofdiagnosingIBD.Moreoveritshighpositivepredictivevalue.