Background and objectives: A collaborative study was done to examine the sensitivity and specificity of assays for the detection of human parvovirus B19 DNA in plasma pools by PCR techniques and to establish a working reagent for B19 DNA testing of plasma pools. Materials and methods: Duplicate samples consisting of a tenfold dilution series of a positive cryosupematant diluted in B19 DN A-negative cryosupematant were sent to 17 laboratories. Results: The sensitivity of the assays varied: 2 laboratories were able to detect the 10^-7 dilution while 1 laboratory failed to detect B19 DNA in any samples. In addition, 5 laboratories obtained false-positive results. Conclusions: In general, laboratories using assays optimised for rapid detection of B19 DNA in serum samples did not perform well, indicating that such rapid methods are not adequate for examination of plasma pools. The 10^-6 dilution was detected by approximately half the laboratories and could be used as the working reagent.