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Home > Patient & Family Resources > Health Library > KOH Preparation
Doctors use the KOH preparation test to find out if you have a fungal infection. This kind of infection can happen in various parts of the body, such as the skin, nails, mouth, or vagina.
KOH is the abbreviation for potassium hydroxide, the solution that is used in the test.
Your doctor may do a KOH test to find out if you have one of these fungal infections:
You don't need to do anything before you have this test.
A doctor or nurse takes a sample by lightly scraping the infected area. Sometimes the doctor will use a swab.
The sample is then placed on a slide with potassium hydroxide (KOH) solution and is gently heated. This solution slowly dissolves the skin cells but not the fungus. The fungus can then be seen with a microscope. Color stains may be used so that the fungus is easier to see.
You may feel a scraping sensation when the doctor or nurse takes the sample. The scraping takes only a few seconds.
It may be uncomfortable if a sample is scraped from under a fingernail or toenail, or if the area is sore, such as when you have thrush.
There is no chance for problems from this test.
Findings of a KOH test may include the following:
Your doctor will talk with you about anything that might keep you from having the test or that may change the test results.
Current as ofMarch 28, 2019
Author: Healthwise StaffMedical Review: Adam Husney MD - Family MedicineMartin J. Gabica MD - Family Medicine
Current as of:
March 28, 2019
Medical Review:Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine
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