Comparison of an enzyme-linked immunoassay and a quantitative indirect fluorescent-antibody test with the conventional indirect fluorescent-antibody test for detecting antibodies to Toxoplasma gondii.

Two new methods for the detection of antibodies to Toxoplasma gondii, an enzyme-linked immunosorbent assay and a quantitative immunofluorescence assay, were evaluated and compared with the conventional indirect fluorescent-antibody slide test. Each of 100 human sera was assayed twice by the three procedures. Both the enzyme-linked immunosorbent assay and the quantitative immunofluorescence assay correlated well with serologically positive (indirect fluorescent-antibody titer greater than or equal to 1:32) and negative sera. The enzyme-linked immunosorbent assay was more specific, but less sensitive, than the quantitative immunofluorescence assay. However, the quantitative immunofluorescence assay was more reproducible and more rapid than the enzyme-linked immunosorbent assay.