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Tests for Bacterial Vaginosis

How It Is Done

You will take off your clothes below the waist. You will have a gown to drape around your waist. You will then lie on your back on an examination table with your feet raised and supported by stirrups. This is similar to having a pelvic examination camera.gif or Pap test.

Your doctor will insert a lubricated tool called a speculum camera.gif into your vagina. The speculum gently spreads apart the vaginal walls, allowing your doctor to see the inside of the vagina and the cervix.

Samples of fluid inside the vagina are then collected with a swab or wooden stick.

How It Feels

You may feel some discomfort when the speculum is put in, especially if your vagina is irritated and tender.

Risks

There is little or no risk in having a bacterial vaginosis test.

Results

Tests for bacterial vaginosis take samples of fluid and cells from the vagina to see if signs of infection are present.

A high vaginal pH, clue cells, and a fishy odor are some signs that bacterial vaginosis is present.

Tests for bacterial vaginosis
Normal

No abnormal vaginal discharge is present on vaginal exam.

A wet mount does not show large numbers of bacteria, such as Gardnerella, that cause bacterial vaginosis.

Few or no clue cells are present.

No fishy odor is present when a potassium hydroxide (KOH) solution is added to a sample of vaginal discharge.

Vaginal pH is in the normal range of 3.8 to 4.5.

Abnormal

A bacterial vaginosis infection is present.

  • A thin, grayish white vaginal discharge is present on vaginal exam. The discharge often looks shiny and has small bubbles.
  • A fishy odor is made when a KOH solution is added to a sample of vaginal discharge.
  • Large numbers of the types of bacteria that cause bacterial vaginosis (such as Gardnerella), clue cells, or both are present on wet mount.
  • Vaginal pH is greater than 4.5.

 

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • If you are having your menstrual period.
  • If you use a vaginal medicine.
  • Having sex or douching 24 hours before this test.

What To Think About

  • Bacterial vaginosis during pregnancy increases a woman's risk of early (preterm) delivery. Because of this risk, it is important to treat bacterial vaginosis during pregnancy with antibiotics.
  • Experts disagree about calling bacterial vaginosis a sexually transmitted infection (STI). A history of STIs or having multiple sex partners increases the chance of developing bacterial vaginosis.

Other Works Consulted

  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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