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Yeast Infection Tests

What is a Yeast Test?

A yeast test can help find out whether you have a yeast infection. Yeast is a type of fungus that lives on your skin and genitals and in your mouth and intestines (gut).

Candidiasis, candidosis, and moniliasis are other names for a yeast infection.

Normally, yeast doesn't cause problems. But if yeast grows out of control, it can cause a bothersome infection that needs treatment. If you're generally healthy, a yeast infection is rarely serious. But in people with weakened immune systems, a yeast infection may become very serious. It may affect the blood, heart, brain, eyes, bones, and other parts of the body. This is called an invasive yeast infection.

Other names: potassium hydroxide preparation, fungal culture; fungal antigen and antibody tests, calcofluor white stain, fungal smear

What is it used for?

A yeast test is used to diagnose yeast infections. There are different methods of yeast testing, depending on where you have symptoms.

Why do I need a yeast test?

Your health care provider may order a test if you have symptoms of a yeast infection. Symptoms depend on where the yeast is growing. Yeast infections tend to grow in moist areas of your skin and mucous membranes.

These are the typical symptoms of some common types of yeast infections, but your symptoms may vary:

Yeast infections on the folds of the skin include conditions such as athlete's foot and diaper rash. Symptoms include:

  • Bright red rash, often with ulcers (open sores)
  • Itching and/or burning
  • Pimples

Vaginal yeast infections are very common. Symptoms include:

  • Genital itching and/or burning
  • A white discharge that looks like cottage cheese
  • Pain when urinating (peeing) and during sex
  • Redness and swelling of the vagina and labia (folds of skin around the vagina)

Yeast infection of the penis is more common if you have diabetes or a foreskin. Symptoms include:

  • Redness
  • Itching and/or burning
  • Rash on the head of the penis that may be painful

Yeast infection of the mouth is called thrush. It is common in young children. Thrush in adults may be a sign of a weakened immune system. Symptoms include:

  • White patches on the:
    • Tongue
    • Inside of cheeks
    • Roof of the mouth
    • Throat
  • Redness or soreness
  • Cotton-like feeling in the mouth
  • Loss of taste
  • Pain while eating

Yeast infection at the corners of the mouth may be caused by thumb sucking, ill-fitting dentures, or frequent licking of the lips. Symptoms include:

  • Cracks and redness at the corners of the mouth

Yeast infection in the nail beds can happen in the fingernails or toenails, but it's more common in toenails. Symptoms include:

  • Discolored nail (yellow, brown, or white)
  • Thick nail
  • Cracks in the nail
  • Pain and redness if the infection is severe

What happens during a yeast test?

The type of test depends on the location of your symptoms.

To test for:

  • A vaginal yeast infection - Your provider will perform a pelvic exam and take a sample of the discharge from your vagina.
  • Thrush - Your provider will look at the infected area in the mouth and may scrape some cells to examine under the microscope.
  • A yeast infection on the skin or nails - Your provider may use a blunt-edged instrument to scrape off a small bit of skin or part of a nail to examine. During this type of test, you may feel some pressure and a little discomfort.

Your provider may be able to tell if you have a yeast infection just by looking at the infected area and examining a sample of the cells under a microscope. If there are not enough cells in the sample to find an infection, you may need a fungal culture test.

During a fungal culture test, the cells in your sample are sent to a lab to grow until there are enough cells to test. Results are often available within a few days. But some yeast grows slowly, so it may take weeks to get a result.

If your provider thinks you may have an invasive yeast infection in your blood or organs, you may have a fungal culture test or other tests on a sample of blood, other fluid, or tissue from the part of your body that may be infected.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a yeast test.

Are there any risks to the test?

There is no known risk to having a yeast test.

What do the results mean?

If your results show that you have a yeast infection, your provider may recommend a prescription or over-the counter antifungal medicine. Antifungal medicines come in many forms for different types of infections, including pills, vaginal creams and suppositories, skin creams, powders, and lotions. Your provider will tell you which treatment is best for you.

It's important to take all your medicine as prescribed, even if you feel better before you finish it. Many yeast infections get better after a few days or weeks of treatment, but certain fungal infections may need treatment for several months or longer before they clear up completely.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a yeast test?

Certain antibiotics can cause yeast to grow out of control. So, be sure to tell your provider about any medicines you are taking.

At-home tests for vaginal yeast infections can tell you if your symptoms are likely to be from a yeast infection. But they may not be able to confirm the diagnosis. It's best to talk with your provider about your symptoms and which test is best for you. This is important, because many symptoms of a vaginal yeast infection are the same as the symptoms from certain sexually transmitted diseases (STDs).


  1. Arya NR, Rafiq NB. Candidiasis. StatPearls Publishing [Internet]. Treasure Island (FL): [last update 2022 Feb 12; cited 2022 Mar 9]; [about 8 screens]. Available from:
  2. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Candidiasis Basics; [reviewed 2020 Oct 30; cited 2022 Mar 9]; [about 6 screens]. Available from:
  3. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Clinical Overview of Invasive Candidiasis; [reviewed 2020 Dec 29; cited 2022 Mar 11]; [about 8 screens]. Available from:
  4. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Ringworm and Fungal Nail Infections Basics; [reviewed 2020 May 22; cited 2022 March 9]; [about 9 screens]. Available from:
  5. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Symptoms of Candidiasis; [reviewed 2021 Feb 5; cited 2022 Mar 11]; [about 4 screens]. Available from:
  6. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Testing and Diagnosis for Candidiasis; [reviewed 2021 Feb 5; cited 2022 Mar 11]; [about 4 screens]. Available from:
  7. Hinkle J, Cheever K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Candida Antibodies; 122 p.
  8. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c2022. Oral Thrush; [cited 2022 Mar 11]; [about 5 screens]. Available from:
  9. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2022. Candidiasis; [reviewed 2021 Apr; cited 2022 Mar 11]; [about 5 screens]. Available from:
  10. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2022. Candidiasis (Yeast Infection); [reviewed 2021 Sep; cited 2022 Mar 11]; [about 6 screens]. Available from:
  11. Mount Sinai [Internet]. Icahn School of Medicine at Mount Sinai; c2022. Skin Lesion KOH Exam; [reviewed 2021 Jun 19; cited 2022 Mar 11]; [about 3 screens]. Available from:
  12. [Internet]. Seattle (WA): OneCareMedia; c2022. At-Home Yeast Infection Test; [modified 2021 Dec 14; cited 2022 Mar 9]; [about 15 screens]. Available from:
  13. [Internet]. Seattle (WA): OneCare Media; c2022. Fungal Tests; [modified 2021 Nov 9; cited 2022 Mar 9]; [17 screens]. Available from:
  14. [Internet]. Seattle (WA): OneCare Media; c2022. Glossary: Culture; [cited 2022 Mar 9]; [about 1 screen]. Available from:
  15. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2022. Health Encyclopedia: Microscopic Yeast Infection; [cited 2022 Mar 9]; [about 6 screens]. Available from:
  16. [Internet]. Washington DC: Office on Women's Health, U.S. Department of Health and Human Services; Vaginal yeast infection; [updated 2019 Apr1; cited 2022 Mar 9]; [about 11 screens]. Available from:

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.