About the Test
Purpose of the test
Vaginal yeast infection testing is performed to diagnose the cause of vaginitis. Vaginitis occurs in the vagina, which is the muscular body part that connects the uterus to the outside of the body. Vaginitis is also called vulvovaginitis because symptoms are often present in the vulva, or the folds of skin around the opening of the vagina.
Vaginitis may be caused by infection with yeast, bacteria, parasites, inflammation, or changes in the natural balance of microorganisms in the vagina. After bacterial infections, yeast infections are the second most common cause of vaginitis in the United States.
Testing for a vaginal yeast infection determines whether your symptoms are caused by an overgrowth of yeast or something else, like a bacterial infection or a sexually transmitted disease (STD). Knowing the cause of vaginitis is necessary to prescribe the proper treatment.
What does the test measure?
Vaginal yeast infection testing is used to evaluate a person’s vagina and look for the cause of vaginitis. This process requires several tests that help to determine if a yeast infection is present.
Yeast is a type of fungus. Most vaginal yeast infections are caused by a type of fungus called Candida. The most common type of Candida, Candida albicans, is normally found in small amounts in your mouth, digestive tract, and skin. Having a small amount of yeast in your vagina usually does not lead to symptoms of vaginitis.
Candida and other microorganisms in the vagina usually keep each other in balance. Certain things can upset this balance, such as changes in hormones, the use of antibiotics, or changes in your immune system. When conditions in the vagina change, an overgrowth of yeast may occur and lead to a yeast infection.
Yeast infection testing typically begins with a physical exam and a discussion of your symptoms. Vaginal pH testing and a microscopic examination of vaginal discharge are then conducted to determine the cause of vaginitis. In some cases, your doctor may recommend other tests such as a culture of vaginal discharge, Gram stain, or nucleic acid amplification testing (NAAT).
Vaginal pH testing
After a physical exam, measuring the pH of your vaginal discharge is usually the first test performed to diagnose or rule out a yeast infection. pH is a measurement of the acidity of a substance on a scale of 1 to 14.
The environment of the vagina is usually acidic. Certain bacterial and sexually transmitted infections can raise the vagina’s pH and make it less acidic. Knowing the pH of your vaginal discharge can help narrow down what underlying problem is causing your symptoms.
Several microorganisms that can cause vaginitis may be seen when vaginal discharge is evaluated under a microscope. This is often referred to as a wet mount. Microorganisms are tiny life forms which can only be seen through a microscope and include bacteria and fungi.
Two tests may be performed during a microscopic evaluation of vaginal discharge:
- Saline wet mount: In this test, vaginal discharge is mixed with a small amount of saltwater on a glass slide. The slide is then examined under a microscope to see if signs of yeast, bacteria, or sexually transmitted infections are present.
- Potassium hydroxide wet mount: Another slide may be prepared with a chemical called potassium chloride (KOH). The use of KOH can make it easier to identify yeast. This test can also trigger a fishy odor, which suggests the presence of certain types of infections. This test is sometimes referred to as a “whiff test.”
A culture of vaginal discharge may be performed if no yeast or other microorganisms are seen under a microscope that account for your symptoms. It may also be ordered for people who have recurrent infections or infections which do not respond to treatment.
A vaginal culture is performed by taking a sample of discharge from the vagina and putting it into a growth medium, which creates ideal conditions for cells to grow in a lab. If growth occurs during a culture test, a sample is further analyzed to determine the cause of vaginitis.
Nucleic acid amplification testing (NAAT) can detect the genetic material of microbes. NAAT may be recommended if certain infections are suspected and also because it offers faster results compared to a culture test.
A Gram stain: is another test that may be used to see if certain germs are present in a sample of vaginal discharge. During a Gram stain, a sample of vaginal discharge is combined with a chemical stain and examined under a microscope. Many microorganisms can be detected and classified during this test. For example, Candida yeast appears purple after a Gram stain.
When should I get a yeast infection test?
Vaginal yeast infection testing may be prescribed when you have symptoms of vaginitis. A vaginal yeast infection commonly causes symptoms such as:
- Pain when urinating
- Pain when having sex
- Vaginal discharge
Many patients with vaginitis don’t have vaginal discharge. When discharge is present, it may be thick, white, clumpy, and odorless.
Vaginal yeast testing may also be performed if your health care provider notices physical signs of a yeast infection during a physical exam. Signs of a yeast infection include:
- Redness of the vulva and vagina
- Swelling of the vulva
- Changes in the skin of the vulva, such as splitting or patchiness
Finding a Yeast Infection Test
How to get tested
Testing for a yeast infection is done in your health care provider’s office or another medical setting. Sometimes a sample of vaginal discharge may be sent to a lab for testing, but often pH testing and a microscopic examination can be performed at your doctor’s office.
Can I take the test at home?
Vaginal yeast infection test kits are available for home testing. However, at-home testing does not include all of the tests that can be performed in a medical office, such as a culture, microscopic examination of discharge, and a physical examination. Types of at-home vaginal yeast infection tests include:
- At-home vaginal pH testing: This test allows you to test your vaginal pH at home using a test strip. When taking this test, it’s important to remember that an at-home vaginal pH test alone cannot determine if vaginal yeast is the source of your symptoms.
- At-home NAAT testing: These at-home vaginal yeast infection tests enable you to collect a sample of vaginal discharge at home and mail it to a lab for analysis. NAAT testing can detect common causes of vaginitis, including yeast, bacterial vaginosis, and the STD trichomoniasis.
Because at-home testing cannot be tailored to match your medical history and symptoms, at-home vaginal yeast infection tests should not be used in place of a visit to your doctor or gynecologist.
More information about at-home testing for yeast infections is available at at-home yeast infection testing.
How much does the test cost?
When a health care provider orders vaginal yeast infection testing, your health insurance will typically cover the collection procedure and lab costs. Laboratory costs depend on how many and what type of tests are performed.
You may have to pay a copayment or a deductible. Your health care provider, lab, and health insurance plan can provide more information about your out-of-pocket costs. You may also ask whether it is necessary to use an in-network lab.
If you do not have medical insurance, you can ask the health care provider’s office about costs and whether payment arrangements or cash discounts are possible. You can also apply for financial assistance at a clinic which focuses on reproductive health care.
Taking a Yeast Infection Test
Yeast infection testing is usually performed on a swab sample collected from your vagina. This sample of vaginal discharge is usually collected during a pelvic examination at a clinic or health care provider’s office.
Before the test
Your health care provider will provide you with instructions on how to prepare for the test. Often, patients will be advised to avoid using creams or medicine in the vagina for two days prior to the test, and to not douche before testing, which describes cleaning or rinsing the inside of the vagina with water or other fluids.
During the test
To collect a specimen for testing, you first remove all clothing below the waist. You lie on your back on an examination table, with your feet elevated in footrests. Your health care provider then inserts an instrument called a speculum into the vagina to hold it open.
A sterile cotton swab is inserted into the vagina to collect a sample of discharge.
Next, the swab and speculum are removed. Obtaining a specimen can take about five minutes.
You may feel some mild discomfort when the speculum is inserted into the vagina.
After the test
There are no risks to obtaining a sample of vaginal discharge. You may resume your normal activities, including driving, immediately after the test.
Yeast Infection Test Results
Receiving test results
Because there are several tests that may be performed to detect a yeast infection, you may get some test results during your initial appointment while other tests may require days to weeks before results are available.
The results of a vaginal pH test are available immediately and may be reported to you by the person performing the test.
Microscopic evaluation is often performed during your medical appointment, and your doctor or nurse may tell you the results of the test before you leave. If your specimen is sent to a lab for analysis, your results may take a day or two. Your doctor or nurse may call you with the results, or they may ask you to return to the office for a follow-up appointment.
If a culture of vaginal discharge is performed, your results may be available in a few days. However, some yeast infections grow slowly in the laboratory, and results may not be available for a week or longer.
Interpreting test results
The results of vaginal yeast infection are interpreted differently depending on which test was performed.
- Vaginal pH: The results of vaginal pH testing are interpreted based on whether the vagina is within a normal range of pH. The normal pH of the vagina is slightly acidic, with a pH of 4 to 4.5. In individuals who are too young to have begun menstruating or who have reached menopause, normal vaginal pH is can be higher. In people with a yeast infection, the vaginal pH is usually normal. A pH level above normal levels may indicate alternative causes for vaginal symptoms, such as bacterial vaginosis or trichomoniasis.
- Microscopic evaluation: A microscopic evaluation of vaginal discharge is interpreted based on what is detected when the sample is viewed under a microscope. Microscopic evaluation may detect yeast, bacteria, or the parasites that cause trichomoniasis. Sometimes bacteria or parasites may be solely responsible for your symptoms, and sometimes yeast infections are present at the same time as other infections.
- Culture of vaginal discharge: The results of a culture indicate whether any microorganisms can be grown in the laboratory and, if so, what organisms are detected. Most vaginal yeast infections are caused by Candida albicans. Other yeast species may be identified using specialized stains and other tests.
Most vaginal infections are caused by bacteria, yeast, or trichomoniasis. The table below describes some of the test results that may be seen in each condition.
|Test||Yeast Infection||Bacterial Infection||Trichomoniasis|
|Vaginal pH||4.0 to 4.5||Over 4.5||5.0 to 6.0|
|Microscopic Examination of Saline Wet Mount||Evidence of buds and branchlike structures found in yeast||Clue cells, which are
vaginal cells with rod-shaped bacteria stuck to them
|Moving trichomonads, the tiny parasite that causes trichomoniasis|
|Microscopic Examination of Potassium Hydroxide Wet Mount||Negative||Fishy odor in majority of patients||May be positive|
|Microscopic Examination with KOH||Evidence of branchlike structures found in yeast||Negative||Negative|
Are test results accurate?
Testing is able to accurately diagnose the cause of symptoms in the majority of patients with vaginitis. Often patients are diagnosed in their health care provider’s office and can initiate treatment immediately.
However, there are challenges to diagnosing vaginal yeast infections. These include:
- Inaccurate pH measurements: Measuring pH is a quick way to rule out other causes of vaginitis because pH is normal in yeast infections but high in other conditions like bacterial vaginosis and trichomoniasis. However, sometimes pH testing is misleading because certain factors, including menstrual blood, semen, douches, medications used in the vagina, and lubricants, can also raise vaginal pH.
- False negative microscopic examination: Microscopic examinations may miss a significant amount of yeast infections. Experts estimate that microscopic examination gives false-negative results in up to half of patients. These patients test negative during a microscopic evaluation and are later proven to have a vaginal yeast infection after a culture test.
- False positive yeast culture tests: Many people have yeast present in their vaginas under normal circumstances. This yeast may grow during a culture test and make it appear that a patient has a yeast infection even when their symptoms are caused by a different condition.
Do I need follow-up tests?
Follow-up tests may be needed if your initial testing does not find a cause of vaginitis symptoms. Follow-up tests may include:
- Repeat testing, preferably when your symptoms are most evident
- A vaginal biopsy, which involves removing a piece of tissue from the vagina, if repeat testing does not detect a cause of symptoms
Questions for your doctor about test results
After undergoing testing for a vaginal yeast infection, you may wish to ask your health care provider some of the following questions:
- Did my vaginal pH suggest my symptoms are caused by yeast or by something else?
- Were you able to perform a microscopic examination here at your office?
- Was any evidence of yeast seen under the microscope?
- Will I need to have a yeast culture or other tests?
- Will I be able to begin treatment for my vaginal symptoms immediately?
Vaginal yeast infection test vs. other yeast infection tests
Under normal conditions, Candida yeast lives in many places on the body without causing illness. If an overgrowth of yeast occurs at one of these sites, it may result in a yeast infection. Yeast infections that occur outside of the vagina include:
- Mouth and throat: When Candida yeast infection occurs in the throat or mouth it is called thrush or oropharyngeal candidiasis.
- Penis: Candida overgrowth on the penis affects 15% to 20% of people with a penis.
- Bladder: If a yeast infection occurs in the bladder, it is called funguria. This type of yeast infection is common in hospitalized patients.
- Skin: Cutaneous candidiasis is a medical term for a yeast infection that affects the skin. Yeast infections can occur on almost any skin on the body. Most commonly, these infections happen in warm and moist areas and in places with creases and folds like the armpits or groin.
In many cases, yeast infections in these parts of the body can be diagnosed based on your symptoms and a physical exam. Doctors will often diagnose yeast infections of the skin, breasts, and penis in this manner.
When yeast infections are suspected in other parts of the body, tests used to diagnose these infections may be similar to testing used to detect vaginal yeast infections. For example, microscopic evaluations and cultures may be used to detect yeast infections occurring in the mouth and throat, penis, breast and skin.
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