Skin lesion KOH exam

How the test is performed:

A scraping of the skin lesion is placed in a solution of potassium hydroxide (KOH) and water and examined under the microscope. The fungus is identified if present.

How to prepare for the test:

Adults:
There is no special preparation for the test.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

You may feel a pressure sensation when the lesion is scraped from the skin.

Why the test is performed:

The test is performed when fungal infections of the skin are suspected.