Clinical Validation and Comparison of Bacterial Vaginosis Detection

Abstract Introduction/Objective Bacterial vaginosis (BV) is considered a top reason for women’s gynecological visits, causing symptoms such as vaginal discharge, foul odor, itching, and burning associated with the alteration of the normal vaginal microbiome. It is often presented as a decrease in Lactobacillus spp. and an increase in anaerobic organisms such as Gardnerella vaginalis and Atopobium vaginae. In response to the demand for more automated and less subjective testing, molecular methods have recently been developed to aid in BV testing. The objectives of this study are to validate and compare the molecular Aptima® Bacterial Vaginosis Assay by Hologic® to the established BV Screen via a Gram stained vaginal smear graded through Nugent scoring at RUSH University Medical Center in Chicago, IL and perform a cost analysis between the testing methods. Methods/Case Report Samples of known BV value were tested on the Panther® instrument to validate the Aptima® Bacterial Vaginosis Assay for accuracy and precision. Clinical samples of vaginal swabs were used to make a Gram stained BV screen for Nugent scoring, then afterwards were placed into Hologic Multitest Aptima® probes for molecular testing on the Panther® instrument. Nugent scoring was performed blind by the molecular test. Molecular results of negative, positive, and invalid were then compared to the Nugent scores: scores of 0-3 for negative/normal vaginal flora, 7-10 for positive BV, and 4-6 for intermediate/altered scores were screened for discrepancy. Results (if a Case Study enter NA) The Aptima® BV Assay tested 52 known samples with 97% accuracy and 100% precision. A total of 80 clinical samples of vaginal swabs used for Gram stained BV screens were run on the Aptima® BV Assay; 61 provided conclusive data for comparative analysis. When compared to the original Nugent scores, the positive percent agreement (PPA) was 77.0% and negative percent agreement (NPA) was 92.9%. Conclusion The Aptima® BV Assay proved to be both accurate and precise in its validation testing. Clinically, it was able to screen for BV in vaginal samples with a good percent agreement to Gram stained BV screens. Further testing of additional clinical samples are to be done to continue analysis. Although the supplies needed to perform a Gram stain cost less than molecular testing, the reimbursement payment for molecular testing is much greater and overall reduces employee time costs for performing the test, making it the more cost effective choice for the laboratory.