Bacterial Vaginosis

Your doctor may only test you for bacterial vaginosis if you:

• Have symptoms.
• Are going to have a hysterectomy or surgical abortion (bacterial vaginosis increases infection risk afterwards).
• Are pregnant and have had a preterm delivery in the past (a past preterm delivery may have been caused by infection).

Your doctor can diagnose bacterial vaginosis based on your history of symptoms, a Reference vaginal exam Opens New Window, and a sample of the vaginal discharge. Reference Laboratory tests to detect signs of bacterial vaginosis may include:

• Wet mount. A sample of vaginal discharge is mixed with a salt (normal saline) solution after placing it on a microscope slide. The prepared slide is examined to identify the bacteria present, to look for Reference white blood cells Opens New Window that point to an infection, and to look for unusual cells called clue cells. The presence of clue cells is the most reliable sign of bacterial vaginosis.
• Whiff test. Several drops of a potassium hydroxide (KOH) solution are added to a sample of vaginal discharge to find out whether a strong fishy odor is produced. A fishy odor on the whiff test suggests bacterial vaginosis.
• Vaginal pH. The normal vaginal Reference pH Opens New Window is 3.8 to 4.5. Bacterial vaginosis usually causes the vaginal pH to rise above 4.5.
• Oligonucleotide probes. This test detects the genetic material (Reference DNA Opens New Window) of bacterial vaginosis bacteria. Oligonucleotide probe testing is very accurate but is not routinely available in most labs.

The presence of clue cells, an increased vaginal pH, and a positive whiff test are enough evidence to treat for bacterial vaginosis.

Bacterial vaginosis may be detected during routine Reference Pap testing Opens New Window. But Pap testing is not a standard or reliable test to diagnose bacterial vaginosis.

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This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Reference Terms of Use. Reference How this information was developed to help you make better health decisions.