Analysis of Standard Methods for Diagnosing Vaginitis

Abstract

We sought to determine whether the standard diagnostic methods for vaginitis behave similarly among HIV-infected and at-risk seronegative women. We performed pairwise comparisons over time (1994-2003) for the different diagnostic methods for bacterial vaginosis (BV) (Nugent score and Amsel criteria), vulvovaginal candidiasis (potassium hydroxide smear and Pap smear), and trichomoniasis (culture, wet mount, and Pap smear) among HIV-infected and at-risk HIV seronegative women in the Women's Interagency HIV Study cohort. We stratified subjects by HIV status and among the HIV-infected women by CD4+ cell count strata. For BV and trichomoniasis, kappa statistics comparing clinical diagnostic methods to laboratory-based methods improved after the first year. Significant differences in overall kappa statistics between HIV-infected and at-risk HIV-seronegative women were found only for vulvovaginal candidiasis where potassium hydroxide smear and Pap smear findings were more tightly correlated among HIV-infected women than among at-risk HIV-seronegative women; among these HIV-infected women, concordance was highest at lower CD4 cell counts. No significant differences in kappa statistics were found for the diagnostic methods of BV or trichomoniasis neither by HIV status nor CD4 cell count strata. The standard diagnostic tests for BV, vulvovaginal candidiasis, and trichomoniasis behave similarly in HIV-infected and at-risk seronegative women. Training and experience are critical for the accurate performance of the diagnostic methods that require clinician interpretation.