Multicenter study establishing the clinical validity of a nucleic-acid amplification-based assay for the diagnosis of bacterial vaginosis

The present study sought to validate the clinical performance of a previously described PCR-based assay for the diagnosis of bacterial vaginosis (BV). A total of 1579 patients were enrolled in 5 locations; samples were classified as BV positive (n=538) or negative (n=1,041) based on an algorithm utilizing quantitative Gram-stain analysis of vaginal discharge and clinical evaluation (Amsel criteria); a next-generation sequencing (NGS) approach to determining diversity of vaginal microbiota was used to resolve discordant results between BV-PCR and Nugent/Amsel. BV-PCR demonstrated a sensitivity of 96.0% (483/503) and a specificity of 90.2% (885/981) when measured against the conventional test standard, with 95 samples (6.0%) being classified as indeterminate. After resolution of discordant results by NGS, including elimination of the PCR indeterminate category, the resolved sensitivity, specificity, and positive and negative predictive values of the BV-PCR assay were 98.7%, 95.9%, 92.9%, and 96.9%, respectively. The results of this study conclusively demonstrate that a relatively simple, 3-biomarker, molecular amplification construct can effectively diagnose BV in symptomatic women. Results generated using this assay were congruent with those obtained using conventional and molecular reference methods.