An amplified ELISA for the detection of parvovirus B19 IgM using monoclonal antibody to FITC.

A new M-antibody capture ELISA for the detection of specific IgM against parvovirus B19 is described. The test uses a monoclonal anti-fluorescein isothiocyanate (FITC) antibody conjugated to horseradish peroxidase to amplify the positive reactions. Serum samples (N = 823) submitted for B19 IgM assay were tested in parallel in the new ELISA and the standard B19 M-antibody capture radioimmunoassay (MACRIA) test. By both tests B19 IgM was detected in 38 (4.6%) samples, and not detected in 771 (94%) samples. One sample was positive in the ELISA test but negative in the RIA and of the 13 sera giving 'equivocal' results in the MACRIA, 6 were positive and 7 negative. If the RIA equivocal results were excluded, the ELISA showed 100% (38/38) sensitivity and 99.9% (771/772) specificity compared to the MACRIA test. The B19 IgM ELISA is a sensitive and specific test with better discrimination between anti B19 IgM positive and negative specimens than MACRIA.