Self-taken vaginal swabs versus clinician-taken for detection of candida and bacterial vaginosis: a case-control study in primary care

Vaginal discharge and vulvitis are common presenting symptoms in general practice. Few studies have specifically looked at the validity of self-taken low vulvovaginal swabs (LVS) for the diagnosis of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV). To assess if patient self-taken LVS are a valid alternative to clinician-taken high vaginal swabs (HVS) for the detection of VVC and BV. Case-control study with the patient acting as their own control in an urban sexual health centre in Newcastle upon Tyne, UK. Females aged 16-65 years attending with symptomatic vaginal discharge, vulval irritation, genital pain, and an offensive genital smell were recruited into the study. Participants took a self-taken LVS before vaginal examination, during which a clinician took an HVS (reference standard). Main outcome measures were the diagnosis of BV or VVC infection. A total of 104 females were enrolled. Of those, 45 were diagnosed with VVC and 26 with BV. The sensitivities of self-taken LVS for VVC and BV were 95.5% and 88.5% respectively. Cohen's κ coefficient showed 'strong agreement' for the detection of both VVC and BV. Vulval itching was the most common symptom associated with VVC (69%), whereas 50% of females diagnosed with BV presented with an offensive discharge. Both symptoms had poor positive predictive values (0.63 and 0.50, respectively). Self-taken LVS appears to be a valid alternative to clinician-taken HVS for detecting VVC and BV infections. Symptoms were found to be a poor indicator of underlying infection.