Incidental Finding of Vaginitis on Liquid-Based Papanicolaou Test Compared to Wet Mount and DNA Probe

Abstract

Objective:

The aim of this study was to evaluate the accuracy of the incidental diagnosis of Trichomonas vaginalis, bacterial vaginosis, and yeast/ Candida on the liquid-based Papanicolaou (Pap) test when compared to wet mount/KOH prep/whiff test, and DNA probe.

Methods:

Six-hundred and nine (609) women who underwent a Pap test also had a wet mount/KOH prep/whiff test, and DNA probe performed evaluating for Trichomonas, bacterial vaginosis, and yeast/candidiasis. Pap specimens showing incidental infection were evaluated for diagnostic accuracy by comparing results with the wet mount/KOH prep/whiff test and the DNA probe.

Results:

Of 609 women evaluated, 145 (23.8%) Pap tests, 161 (26.4%) wet mount/KOH prep/whiff tests, and 365 (59.9%) DNA probes noted the presence of vaginal infections. The specificity and positive predictive value of the Pap test, when compared to the DNA probe, were: 99.6% and 93.1% for Trichomonas; 99.3% and 97.1% for bacterial vaginosis; and 96.3% and 61.5% for yeast/Candida. The same calculations were done comparing the Pap test to the wet mount/KOH prep/whiff test and were: 98.1% and 45.0% for Trichomonas; 91.5% and 41.4% for bacterial vaginosis; and 92.6% and 17.3% for yeast/ Candida. The sensitivities of the wet mount/KOH prep/whiff test for the diagnosis of trichomoniasis, bacterial vaginosis, and candidiasis were only 31.0%, 23.4%, and 33.3%, respectively.

Conclusions:

The incidental finding of Trichomonas or bacterial vaginosis on the liquid-based Pap test can be considered an accurate diagnosis, with a false-positive rate of less than 1%; it warrants no further confirmatory testing. This could not be demonstrated for the finding of yeast/Candida, which warranted further evaluation.