Nguyen, DungSimmonds, PeterSteenhuis, MauriceWouters, EliseDesmecht, DanielGarigliany, MutienRomano, MartaBarbezange, CyrilMaes, PietVan Holm, BramMendoza, JoaquínOyonarte, SalvadorFomsgaard, AndersLassaunière, RiaZusinaite, EvaResman Rus, KatarinaAvšič-Županc, TatjanaReimerink, Johan HjBrouwer, FionaHoogerwerf, MariekeReusken, Chantal BemGrodeland, GunnveigLe Cam, SophieGallian, PierreAmroun, AbdennourBrisbarre, NadègeMartinaud, ChristopheLeparc Goffart, IsabelleSchrezenmeier, HubertFeys, Hendrik Bvan der Schoot, C EllenHarvala, Heli2023-02-092023-02-092021http://hdl.handle.net/10668/18180We compared the performance of SARS-CoV-2 neutralising antibody testing between 12 European laboratories involved in convalescent plasma trials. Raw titres differed almost 100-fold differences between laboratories when blind-testing 15 plasma samples. Calibration of titres in relation to the reference reagent and standard curve obtained by testing a dilution series reduced the inter-laboratory variability ca 10-fold. The harmonisation of neutralising antibody quantification is a vital step towards determining the protective and therapeutic levels of neutralising antibodies.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/EuropeSARS-CoV-2convalescent plasmaneutralising antibodiesstandardisation, COVID-19Antibodies, NeutralizingAntibodies, ViralCOVID-19EuropeHumansImmunization, PassiveSARS-CoV-2COVID-19 Serotherapyresearch article34240697open access10.2807/1560-7917.ES.2021.26.27.21005681560-7917PMC8268650https://www.eurosurveillance.org/deliver/fulltext/eurosurveillance/26/27/eurosurv-26-27-2.pdf?itemId=%2Fcontent%2F10.2807%2F1560-7917.ES.2021.26.27.2100568&mimeType=pdf&containerItemId=content/eurosurveillancehttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC8268650/pdf