The clinical and laboratory diagnosis of Trichomonas vaginalis infection.

One hundred consecutive female patients attending an inner-city clinic for treatment of sexually transmitted diseases were evaluated for the presence of Trichomonas vaginalis by history, physical examination, 0.85% NaCl wet mount, Papanicolaou smear, and culture. Of the 100 women, 54 were found to be harboring the parasite, as determined by one or more positive diagnostic tests. This prevalence corresponds with that reported previously. The information gained from the history (symptoms and phase of menstrual cycle) and physical examination correlated poorly with results of cultures for T. vaginalis; the organism was isolated more often than symptoms or physical findings would have indicated. Culture was the most sensitive of diagnostic techniques; 48 (89%) of the 54 patients were identified by this method. The Papanicolaou smear detected 35 infections (65%), and the 0.85% NaCl wet mount, 28 (59%). The simplest and most efficient technique for screening women for infection with T. vaginalis may be the Papanicolaou smear, since it is part of the annual physical examination.