Evaluation of three commercial enzyme immunoassays for toxoplasma and cytomegalovirus antibodies.

Three commercially available enzyme immunoassays (EIAs) were evaluated for specificity and sensitivity compared to immunofluorescent assays (IFAs) for detection of IgG and IgM antibodies to Toxoplasma gondii (Toxo) and Cytomegalovirus (CMV). A panel of 78 sera were tested, including specimens known to contain Toxo IgG or IgM, CMV IgM or IgM, antinuclear antibodies (ANA), antimitochondrial antibodies (AMA), and rheumatoid factor (RF). Linear correlation analysis comparing EIA and IFA results showed that the statistical relationship between the two assay methods was relatively weak (correlation coefficients ranging from 0.33 to 0.86). Qualitative correlation showed that the EIA methods agreed with IFA results in most cases. One manufacturer's products (Diamedix Corp.) gave consistently better sensitivity, specificity, and intra-assay reproducibility values than the other two systems (Clinical Sciences, Inc., and Whittaker Bioproducts). ANA, AMA, and RF did not appear to interfere with any EIAs.