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Test Code LAB251 KOH: Microscopic Examination

Performing Laboratory

Eisenhower Medical Center


Main Lab - Microbiology


Main Lab: Mycology (Fungus)


Skin, Nails, Hair

Specimen Containers

0.5 mL Sterile Saline in Sterile Tube

Tubes can be obtained from laboratory.

Collection Volume


Procedural Instructions

The KOH prep is used to demonstrate the presence of fungi in tissue, usually skin scales, nail scrapings, or hair. The KOH digests other cellular elements more rapidly than fungi, thus clearing the specimen and leaving fungal elements more clearly visible.

1. Skin: Clean the involved area with 70% alcohol. With sterile blade, scrape off scales at the edge of the lesion. Place

     in a sterile container.

2. Nails: Obtain specimen from the deeper layers of the nail. Place in a sterile container.

3. Hair: Select hairs that are broken with twisted grayish stubs or by their bright yellowgreen fluorescence when 

     examined under Wood's lamp. Place in a sterile container.

4. Other Specimens: Collect in a sterile container without any preservative or transport media.


Transport Requirements

Deliver ASAP