A rapid and specific dot-enzyme immunoassay (DIBA) using monoclonal antibody was introduced for detection of Trichomonas vaginalis antigen in vaginal and urethral materials. The results of DIBA were compared with culture findings of the parasite in 245 female patients. Taking culture as the reference method, DIBA had a sensitivity of 92% and a specificity of 93%. The predictive value of a positive test was 98% and that of a negative test 77%. The efficacy of wet mount, culture and DIBA were compared in 134 women with trichomonal infection. The most sensitive method was cultivation with a positivity of 99.3%. DIBA was as sensitive as the wet mount (92%). In 51 sexual partners of women with trichomoniasis DIBA proved to be ineffective. The sensitivity of the assay with corpuscular antigen of T vaginalis was 1 x 10(4) cells/ml, with soluble antigen 47 micrograms/ml. Specificity of the assay was confirmed by lack of any cross-reactivity with Trichomonas tenax. Tritrichomonas mobilensis and Candida albicans.