Comparison of a latex agglutination test with other serological tests for the measurement of antibodies to Toxoplasma gondii.

Abstract

Sera (100) from 49 patients with glandular toxoplasmosis were examined by a latex agglutination test, the dye test, an indirect hemagglutination test and a double antibody sandwich enzyme linked immunosorbent assay (ELISA) for antitoxoplasma IgM. The results support previous findings that the dye test, indirect hemagglutination test and latex agglutination test measure different antibodies to T. gondii. In early glandular toxoplasmosis, when specific IgM was detected, the titers of both the latex agglutination test and the indirect hemagglutination test were lower than the dye test. Repeat specimens from 11 of the patients showed 4 cases in which the latex agglutination test titers never exceeded 1/256, whereas both the dye test and the indirect hemagglutination test showed significant titers and specific IgM was detected in every case. The latex agglutination test should not be used as a substitute for the dye test in the serological diagnosis of glandular toxoplasmosis. All sera giving a positive latex agglutination test result should be referred for further tests. A combination of the dye test and double antibody sandwich ELISA gives the most reliable serological diagnosis of early glandular toxoplasmosis.