Comparing BD Affirm VPIII to Xpert Xpress MVP and BD MAX Vaginal Panel for the diagnosis of vaginal infections

ABSTRACT BD Affirm VPIII, a non-amplified molecular test for the detection of Candida, Trichomonas vaginalis (TV), and Gardnerella vaginalis (GV), was compared to two nucleic acid amplification tests (NAATs), the Xpert Xpress MVP and BD MAX Vaginal Panel, to estimate its sensitivity and specificity for the diagnosis of vaginitis/vaginosis. Women ≥14 years old, seeking care with symptoms of vaginitis (vaginal discharge, odor, vulvar or vaginal itch, irritation, and burning), provided self-collected vaginal samples for the Xpert Swab Specimen Collection (Xpert Xpress MVP), BD Molecular Swab Collection (BD MAX Vaginal Panel), and BD Affirm Ambient Temperature Transport System (BD Affirm VPIII). True positive and negative results were defined as concordant results on both NAATs. Agreement between the NAATs was 96% for bacterial vaginosis (BV), 95% for Candida, and 100% for TV. Based on both NAATs, the prevalence of BV in the population was estimated to be 42.8% (118/276), 28.3% (78/276) for Candida, and 5.1% (14/276) for TV. The BD Affirm VPIII detected only 43% of TV and 56% of Candida. While the sensitivity of GV for BV was 89.7% (95% confidence interval [CI]: 82.6–94.5), the specificity was 76.2% (95% CI: 68.4–82.9). Of women with no BV, Candida , or TV by NAAT, 29.5% would have been misdiagnosed based on Affirm VPIII. Reliance on GV for the diagnosis of BV results in false positives in women without BV and could trigger unwarranted treatment. The inadequate sensitivity of Affirm VPIII for Candida and TV and poor specificity for BV limits its utility in clinical settings for women with symptomatic vaginitis. IMPORTANCE Vaginal infections are common among women of reproductive age, with substantial costs for women and health systems. Point-of-care methods widely used in clinical practice to diagnose bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis include microscopy, pH testing, and amine odor. Microscopy for motile trichomonads or the pseudohyphae of Candida is insensitive because Candida or Trichomonas vaginalis can cause symptoms even when present in concentrations not detectable by direct microscopy. When microscopy is not available, the U.S. Centers for Disease Control and Prevention has recommended the use of other tests, including nonamplified DNA probe technology. Our study compared this system to two FDA-cleared amplified testing systems for the diagnosis of vaginitis. The nonamplified system was insensitive for the detection of Candida and Trichomonas vaginalis and nonspecific for bacterial vaginosis, which could result in inappropriate treatment and misdiagnosis, limiting its clinical utility for use in women with vaginitis symptoms.