Evaluation of reliability of self-collected vaginal swabs over physician-collected samples for diagnosis of bacterial vaginosis, candidiasis and trichomoniasis, in a resource-limited setting: a cross-sectional study in India

Objectives: Self-collected vaginal swabs can facilitate diagnosis of vaginal discharge (VD) in resource-limited settings, provided reliability of the method is established. The aim of this study was to evaluate the concordance between self-collected and physician-collected vaginal swabs for aetiological diagnosis of VD and to determine the prevalence of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and trichomonas vaginitis (TV).

Methods: A total of 550 females (median age: 32 years; range: 18-45 years) attending two sexually transmitted infection/reproductive tract infection (STI/RTI) clinics with VD from January 2015 to May 2016 were included in the study after obtaining written informed consent. Swabs were self-collected by patients after instructions and subsequently by a physician under speculum examination. Samples were processed for standard bedside tests, Gram staining, wet mount and culture (gold standard) according to the national guidelines. Concordance between the two methods was determined by the Cohen's kappa value.

Results: BV, VVC and TV were diagnosed in 79 (14.4%), 144 (26.2%) and 3 (0.5%) patients, respectively. VVC coexisted with BV in 58 (10.5%) patients. There was no coinfection of TV with BV or VVC. Candida albicans was isolated in 84 (58.3%) VVC cases. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of self-collected swabs for diagnosing BV was 91.1%, 100%, 100% and 98.5%, respectively, while for the C. albicans VVC and TV, sensitivity, specificity, PPV and NPV all were 100% as compared with physician-collected swabs. Highly concordant results were obtained between two methods by the Kappa values of 0.95 (BV), 0.99 (VVC) and 1.0 (TV).

Conclusion: The comparative performance of self-collected and physician-collected vaginal swabs establishes self-collection of samples for BV, VVC and TV as a viable alternative tool in the management of STIs/RTIs, especially in peripheral and resource-constrained settings. This would be effective in implementing the diagnostic approaches for STIs/RTIs in community-based surveillance studies at national or regional level and therefore strengthening the National STI/RTI Control Programme.