Comparison of direct fluorescent antibody, acridine orange, wet mount, and culture for detection of Trichomonas vaginalis in women attending a public sexually transmitted diseases clinic.

To define the performance characteristics of two newer tests for Trichomonas vaginalis (TV), the authors compared direct fluorescent antibody (DFA) (mixed monoclonal antibody, Integrated Diagnostics, Inc, Berkeley, CA) and acridine orange (AO) tests to standard wet mount (WM) preparations and culture (modified Diamond medium) of vaginal wash specimens in consecutively examined women presenting to a public sexually transmitted diseases (STD) clinic. Cultures for Neisseria gonorrhoeae (GC), Chlamydia trachomatis (CT), and yeast were also performed on all patients. Of 104 women, 59 (57%) were infected with one or more pathogens. Trichomonas vaginalis was detected by WM and/or culture in 38 (37%) women and was the most prevalent infection. Of the 38 patients with TV, 95% were detected by culture, 83% by DFA, 66% by AO, and 66% by WM. An additional patient was DFA positive but negative for TV by all other methods. The sensitivity of DFA was superior to AO and WM in women with TV infection alone (96% compared to 67% and 53%, respectively). It was comparable to AO and WM in women with multiple infections (67% compared to 53% and 73%). Even in the presence of other pathogens, DFA appears to be a reasonable alternative to culture for detection of TV. In addition, DFA is rapid, easy to perform, and relatively inexpensive.