Experience with routine vaginal pH testing in a family practice setting

Despite recommendations by Centers for Disease Control and the American College of Obstetricians and Gynecologists, pH testing is infrequently performed during the evaluation of vaginitis. Consequently, little information exists on its use in a primary care setting.

The aim of this study was to describe our experience with routine pH testing, particularly the relationship between symptoms, pH and wet-mount microscopy.

A retrospective chart review was performed on 203 consecutive cases evaluated for vaginitis by wet-mount microscopy.

Of the 203 cases, 21 had normal pH and no symptoms and 182 had symptoms, elevated pH or both; 85% of cases had abnormal wet-mount findings, including 75% with clue cells, 14% with Trichomonas vaginalis, 13% with yeast and 14% with mixed infections. Asymptomatic infection was present in 42% of cases with clue cells alone, 44% of cases with Trichomonas vaginalis alone, 38% of all trichomoniasis cases and 33% of cases with mixed infections. Elevated pH was associated with clue cells (p < 0.001), trichomoniasis (p = 0.01) and mixed infections (p = 0.003). Normal pH was associated with negative wet mount (p < 0.001) and to a lesser degree with uncomplicated vulvovaginal candidiasis (p = 0.06).

Routine pH testing increased detection of trichomoniasis and bacterial vaginosis by prompting microscopy in a significant proportion of asymptomatic cases.