Molecular testing for Trichomonas vaginalis in women: results from a prospective U.S. clinical trial

Abstract

Trichomoniasis is a common sexually transmitted disease associated with preterm birth, low birth weight, and increased susceptibility to infection with other pathogenic sexually transmitted microorganisms. Nucleic acid amplification tests for Trichomonas vaginalis have improved sensitivity for detecting infected individuals compared to existing culture-based methods. This prospective, multicenter U.S. clinical trial evaluated the performance of the automated Aptima T. vaginalis assay for detecting T. vaginalis in 1,025 asymptomatic and symptomatic women. Vaginal swab, endocervical swab, ThinPrep PreservCyt, and urine specimens were collected. Subject infection status was determined by wet-mount microscopy and culture. Aptima T. vaginalis assay performance was determined for each specimen type by comparison to subject infection status. Of 933 subjects analyzed, 59.9% were symptomatic. Aptima T. vaginalis clinical sensitivity and specificity were, respectively, 100% and 99.0% for vaginal swabs, 100% and 99.4% for endocervical swabs, 100% and 99.6% in ThinPrep samples, and 95.2% and 98.9% in urine specimens. Aptima T. vaginalis performance levels were similar in asymptomatic and symptomatic subjects. This study validates the clinical performance of the Aptima T. vaginalis assay for screening asymptomatic and symptomatic women for T. vaginalis infection.

Fig. 1.

Of 1,025 subjects enrolled at 9 sites, there were 933 evaluable subjects (91.0%), from which we planned to collect 3,732 samples (933 subjects with 4 samples each). Of these, 382 (10.2%) samples were either missing or considered nonevaluable (expired). Of the 3,350 evaluable samples (738 urine, 877 vaginal swab, 922 endocervical swab, and 813 ThinPrep samples), 3,343 (99.8%) had final valid results; seven (0.2%; 3 urine, 2 vaginal swab, and 2 endocervical swab) samples had final invalid results and were not included in the analyses. ATV, Aptima T. vaginalis.