Detection of Toxoplasma-specific IgM in cord blood sera by antibody-class capture enzyme-linked immunosorbent assay.

An antibody class capture (ACC) enzyme-linked immunosorbent assay (ELISA) utilizing an F(ab)2 conjugate was established and its specificity and reproducibility were determined. The test was further validated by comparing its results with those obtained by 2 overseas reference laboratories which used the indirect immunofluorescence antibody test (IIFT) for Toxoplasma-specific IgM. It was found that the F(ab)2ACC-ELISA was not affected by the presence of rheumatoid and antinuclear factor in serum, that it was reproducible (coefficients of variation less than 10.0%), and that it compared well with tests currently used overseas. ELISA was then used to test for the presence of Toxoplasma-specific IgM in cord blood sera. The results obtained to date are consistent with the hypothesis that the prevalence of congenital toxoplasmosis in the population of Adelaide is less than 1/2,000.