KOH (potassium hydroxide) preparation for oral candidiasis (thrush)
The KOH preparation test is used to find out whether oral candidiasis (thrush) is present in a person's mouth. A sample of skin is taken from the person's mouth by lightly scraping the white patches.
The sample is then placed on a slide with potassium hydroxide (KOH) solution and gently heated. This solution slowly dissolves the skin cells but not the yeast cells. The yeast cells can then be seen with a microscope. Color stains may be used so that the yeast cells are easier to see.
Skin Problems: Prevention - Videos
Any time you’re outside, you’re getting sun exposure, even if you’re not trying to tan. This video offers 10 tips to limit sun damage. Video: Is a Healthy Tan Possible?
Read the Skin Problems: Prevention - Videos article > >
Why It Is Done
If a person has white patches in the mouth or on the tongue, a KOH test may be done to find out whether the person has thrush.
Results
Findings of a KOH test may include the following.
Normal
No yeast or other fungi are present in the sample from the person's mouth.
Abnormal
Yeast or other fungi are present in the sample from the person's mouth.
What To Think About
In general, a KOH test is not needed to diagnose thrush. A doctor usually can diagnose thrush by looking at the white patches in a person's mouth.
If thrush does not respond to prescribed medicines, a fungal culture may be done to find out whether drug-resistant strains of yeast are causing the infection.
Complete the medical test information form (PDF)
(What is a PDF document?) to help you prepare for this test.
WebMD Medical Reference from Healthwise
Build Your Perfect Skin Care Routine
Beautiful, clear skin starts with the right routine. Build yours here.
