The skin lesion KOH exam is a test to diagnose a
Potassium hydroxide examination of skin lesion
How the Test is Performed
The health care provider scrapes the problem area of your skin using a needle or scalpel blade. The scrapings from the skin are placed on a microscope slide. Liquid containing the chemical
How to Prepare for the Test
There is no special preparation for the test.
How the Test will Feel
You may feel a scratching sensation when the provider scrapes your skin.
Why the Test is Performed
This test is done to diagnose a fungal infection of the skin.
No fungus is present.
What Abnormal Results Mean
Fungus is present. The fungus may be related to
If the results are uncertain, a
There is a small risk of bleeding or infection from scraping the skin.
Chernecky CC, Berger BJ. Potassium hydroxide preparation (KOH wet mount) - specimen. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:898-899.
Fitzpatrick JE, High WA, Kyle WL. Diagnostic techniques. In: Fitzpatrick JE, High WA, Kyle WL, eds. Urgent Care Dermatology: Symptom-Based Diagnosis. Philadelphia, PA: Elsevier; 2018:chap 2.
Review Date: 16/04/2019
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 ©2019 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 Health. Please discuss with your doctor any questions or concerns you may have.