Serodiagnosis of Trichomonas vaginalis infection by the indirect fluorescent antibody test.

The indirect fluorescent antibody test was used to detect antibodies to Trichomonas vaginalis in 200 antenatal patients. A total of 104 (52%) gave a positive reaction with antigen prepared from cultures of trichomonas isolated from seven of the patients. Antitrichomonal antibody was detected at a 1/4 dilution in 90% of patients with proven trichomoniasis, while the highest dilution at which antibody was detected was 1/32. IgG rather than IgM appeared to be the antibody class involved. Of those patients with no demonstrable trichomonal infection, 17% gave positive reactions at 1/4 dilution, while 64% had no demonstrable antibody. One of 30 children under 11 years of age gave a positive reaction.