A proficiency testing study to evaluate laboratory performance for the detection of different genotypes of parvovirus B19

Background and Objectives In Europe, it is a regulatory requirement that parvovirus B19 (B19V) DNA nucleic acid amplification technique-based testing is performed on plasma pools for certain classes of plasma-derived medicinal products. This proficiency testing study set out to examine the ability of public quality control laboratories and plasma fractionation organizations to detect different genotypes of B19V using nucleic acid amplification technique-based assays. Materials and Methods Laboratories were supplied with cloned DNAs representing the main genotypes of B19V. All samples were adjusted to equivalent copy number and were distributed as part of a routine external quality assessment programme investigating the evaluation of B19V containing plasma samples by these laboratories. The plasmid clones were distributed to 25 laboratories, representing 13 quality control laboratories and 12 manufacturers of plasma derivatives. The criteria for acceptable detection of the different genotypes of B19V DNA was based upon the maximum theoretical efficiency for polymerase chain reaction amplification. Proficient laboratories were deemed to be those reporting results within 1 log(10) dilution for each of the different virus genotypes. Results Data were returned by 23 of the participating laboratories. Some laboratories returned data for more than one type of assay and in total 27 data sets were analysed. Nine of the participating laboratories were able to successfully detect all the virus genotypes according to the applied criteria, all except one used in-house assays. Conclusions The results of the study highlight that there are still discrepancies in the detection of a broad spectrum of B19V genotypes, with implications for batch release testing.