HVS (high vaginal swab)

High vaginal swabs HVS

• are often used to diagnose causes of vaginal discharge but they are of limited value
  
  
• bacterial vaginosis (BV) may be under-diagnosed if no other diagnostic criteria are used
  
  
• reporting of commensal bacteria can cause anxiety and lead to overtreatment

HVS may be used to aid the diagnosis of BV, vulvovaginal candidiasis (VVC), trichomonas vaginalis (TV) or other genital tract infections (e.g. streptococcal organisms) but their use should generally be reserved for the following situations:

• when symptoms, signs and/or pH are inconsistent with a specific diagnosis
• pregnancy, postpartum, post-abortion or post-instrumentation
• recurrent symptoms
• failed treatment

If TV is suspected an HVS can be taken from the posterior fornix but sensitivity may be low because motility reduces with transit time. Therefore, referral to GUM is recommended for confirmation by wet microscopy +/- culture, and also for partner notification. Laboratories may not routinely perform wet microscopy or TV culture so suspected TV should be mentioned on the laboratory request form

Reference:

• 1) FSRH and BASHH Guidance (February 2012) Management of Vaginal Discharge in Non-Genitourinary Medicine Settings.