What is a yeast infection test?

A yeast test can help find out whether you have a yeast infection. Candidiasis, candidosis, and moniliasis are other names for a yeast infection.

Yeast is a type of fungus. Fungi (more than one fungus) are plant-like life forms that live everywhere, including on your skin, genitals, mouth, and intestines (gut). Usually, yeast doesn't make you sick. But if yeast grows out of control, it can cause an infection that needs treatment.

If you're generally healthy, a yeast infection is rarely serious. But for some people, a yeast infection may become very serious. It may affect the blood, heart, brain, eyes, bones, or other parts of your body. This is called an invasive yeast infection.

Invasive infections are usually not a risk for healthy people. But you may be at higher risk of an invasive infection, for example if you have a weakened immune system or a central venous catheter, or if you've had surgery or chemotherapy.

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 your 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:

• Itching and/or burning in your vagina and vulva (the external female genital organs)
• A white discharge that looks like cottage cheese
• Pain when urinating (peeing) and during sex
• Redness and swelling of your vagina and labia (folds of skin around the vagina)

Yeast infection of the penis is more common if you have diabetes or a foreskin (you are not circumcised). 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.

• 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 your mouth and may scrape some cells to examine under a 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. Your sample is put in a dish with a special substance that allows cells to grow until there are enough 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?

You may have a higher risk of a yeast infection if you:

• Are taking antibiotics. Certain antibiotics can cause yeast to grow out of control. So, be sure to tell your provider about any medicines you are taking.
• Are pregnant. Hormonal changes may increase your risk of yeast infections.
• Have HIV. People with HIV have a higher risk of esophageal candidiasis.

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 of certain sexually transmitted infections (STIs).