Vaginal Wet Mount

Medically Reviewed by Jennifer Robinson, MD on September 02, 2022
3 min read

A vaginal wet mount, also called a wet prep or vaginal smear, is a test done to find the cause of vaginitis, an inflammation of the vagina. Your doctor will usually order the test if you’re having symptoms like itching, a discharge, or pain.

It’s not the same as a Pap test, which is a regularly scheduled exam that looks for cancerous or precancerous cells in the cervix. But you could have a vaginal wet mount and a Pap smear at the same appointment.

There are different causes of vaginitis. Your doctor might do a wet mount to help confirm or rule out some different causes of the inflammation, including:

Vulvitis. An inflammation of the vulva -- the folds of skin just outside the vagina.

Bacterial vaginosis. This is the most common type of vaginitis. It happens when bacteria replace healthy vaginal cells.

Yeast infection. An overgrowth of the fungus candida is the second most common type of vaginitis. Candida is normally found in small amounts in the vagina.

Trichomonas vaginitis. Also known as “trich,” this infection is caused by a parasite and is spread through sexual contact.

To find out if you have other sexually transmitted diseases, such as chlamydia, gonorrhea, or herpes, you’ll need other types of tests.

Your doctor or nurse will examine your vagina. If there’s obvious discharge, they may know what it is right away. For example, a yeast infection produces white, lumpy discharge. But with a bacterial infection, the discharge is thin and smells like fish. Still, your doctor might do a vaginal wet mount to be sure the culprit is what they think it is.

During the test, you’ll lie on your back with your feet above your hips, usually in stirrups. A smooth device called a speculum is put into your vagina to gently widen it. The speculum might feel a bit cold. You may feel some temporary discomfort when it’s first inserted, especially if you have vaginitis.

Your nurse or doctor will use a thin cotton swab to collect cells from the vaginal wall. They’ll smear the cells on a small microscope slide and mix them with a saline solution. They’ll view the slide under a microscope.

Your doctor will know what type of vaginitis you have, based on what they see on the slide. The slide may be sent to a lab to check for white blood cells, yeast, bacteria, parasites, or other signs of infection.

A whiff test, or KOH test, may be done on the vaginal sample during the wet mount test. A few drops of potassium hydroxide (KOH) are mixed with the sample. The KOH kills bacteria and leaves only yeast behind, revealing if you have a yeast infection. If mixing the two creates a strong fishy odor, then you have bacterial vaginosis.

If your doctor thinks you might have a sexually transmitted disease such as herpes, chlamydia, or gonorrhea, more testing may be needed.

It can take a few days to get wet mount test results.

For the most accurate vaginal wet mount test results:

  • Don’t have sex before the test.
  • Don’t, douche or use tampons before the test.
  • Don’t have a vaginal wet mount during your period. If you’re having your period, wait until it’s over to have a vaginal wet mount. Blood can make it hard to get clean test results.
  • Don’t use yeast infections medications for 3 days before the test.
  • If you’re pregnant or think you might be, tell your doctor before the test. They’ll test you if it’s safe to have this test.

A gynecological exam of any kind can be a little awkward. You may also feel embarrassed if you have symptoms like a smelly discharge. But keep in mind that these types of infections are common. Your gynecologist sees people with similar complaints all day and would not judge you. Remember, a vaginal infection can lead to serious complications if it’s not treated right away.