EUVAC.NET collaborative study: evaluation and standardisation of serology for diagnosis of pertussis

As part of the new EUVAC.NET contract with ECDC (Pertussis Work Area 4), a collaborative study was organised in July-December 2010. Two well-defined reference preparations with high and low IgG antibodies to pertussis toxin (PT), were sent to participants. The purposes of this study were to assess current laboratory performance of serological assays for pertussis; to compare in-house reference preparations that are currently used by participants for the serological assay; and to identify needs for standardisation of the serological assay. Reference Laboratories in Europe currently performing serological assays for the diagnosis of pertussis by measuring antibody to PT, were invited to participate in the study. A total of 17 laboratories/countries participated in this study. Results were reported from a total of 9 participants who used in-house ELISA assays and 10 participants who used commercial kits. All participants using in-house ELISA with purified PT coating plates distinguished the 2 preparations and gave results that were comparable to the expected values. A total of 6 commercial kits included in the study showed different results. The kits coated with mixture antigens did not appear to be able to give results that were correlated to the WHO reference preparations.