The skin lesion KOH exam is a test to diagnose a fungal infection of the skin.
Potassium hydroxide examination of skin lesion; Fungal wet prep
The health care provider scrapes the lesion off your skin, using a blunt edge such as the edge of a microscope slide. The scrapings from the skin lesion are placed in liquid containing potassium hydroxide (KOH) and examined under the microscope. KOH destroys all non-fungal cells, which makes it easier to see if there is any fungus present.
There is no special preparation for the test.
You may feel pressure when the doctor scrapes the lesion off your skin.
This test is done to diagnose a fungal infection of the skin.
Normally, there is no fungus.
The KOH smear shows fungus, which may be related to ringworm, athlete's foot, jock itch, or another fungal infection.
There is a small risk of bleeding or infection from scraping the lesion.
Review Date: 4/15/2009
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright ©2010 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.
Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Medical Center. Please discuss with your doctor any questions or concerns you may have.