SARS-CoV-2 neutralising antibody testing in Europe: towards harmonisation of neutralising antibody titres for better use of convalescent plasma and comparability of trial data.
Nguyen D., Simmonds P., Steenhuis M., Wouters E., Desmecht D., Garigliany M., Romano M., Barbezange C., Maes P., Van Holm B., Mendoza J., Oyonarte S., Fomsgaard A., Lassaunière R., Zusinaite E., Resman Rus K., Avšič-Županc T., Reimerink JH., Brouwer F., Hoogerwerf M., Reusken CB., Grodeland G., Le Cam S., Gallian P., Amroun A., Brisbarre N., Martinaud C., Leparc Goffart I., Schrezenmeier H., Feys HB., van der Schoot CE., Harvala H.
We 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.