Diagnose Bacterial Vaginosis

How is Bacterial Vaginosis Diagnosed?

BV can be diagnosed by the use of clinical or Gram-stain criteria. Clinical criteria require three of the following symptoms or signs:

• a homogeneous, white, noninflammatory discharge that smoothly coats the vaginal walls;
• the presence of clue cells on microscopic examination;
• a pH of vaginal fluid >4.5; and
• a fishy odor of vaginal discharge before or after addition of 10% KOH (i.e., the whiff test).

When a Gram stain is used, determining the relative concentration of the bacterial morphotypes characteristic of the altered flora of BV is an acceptable laboratory method for diagnosing BV.

Culture of G. vaginalis is not recommended as a diagnostic tool because it is not specific.

However, a DNA probe based test for high concentrations of G. vaginalis (Affirm ™ VP III, manufactured by Becton Dickinson, Sparks, Maryland) may have clinical utility.

Cervical Pap tests have limited clinical utility for the diagnosis of BV because of low sensitivity.

Other commercially available tests that may be useful for the diagnosis of BV include a card test for the detection of elevated pH and trimethylamine (FemExam ® test card, manufactured by Cooper Surgical, Shelton, Connecticut) and prolineaminopeptidase (Pip Activity TestCard ™, manufactured by Litmus Concepts, Inc., Santa Clara, California).