KOH preparation
Pronunciation: K-O-H prep-a-RAY-shun
A laboratory test using potassium hydroxide to dissolve skin cells and reveal fungal elements for diagnosing superficial fungal infections.
Full Definition
KOH (potassium hydroxide) preparation is a rapid diagnostic test commonly performed in pediatric dermatology clinics to identify fungal infections of the skin, hair, and nails. The procedure involves collecting skin scales, hair samples, or nail clippings, treating them with 10-20% potassium hydroxide solution, and examining under microscopy for fungal hyphae, spores, and other fungal elements. In children, this test is frequently used to diagnose tinea capitis, tinea corporis, and other dermatophyte infections. The test can be performed immediately in the clinic, providing rapid results to guide treatment decisions.
Usage
Usage note: Always spell out 'potassium hydroxide' on first use, then use KOH abbreviation.
In Context
- "KOH preparation of scale from the lesion was positive for septate hyphae consistent with dermatophyte infection." — Laboratory result documentation
- "Negative KOH preparation; will consider alternative diagnoses for the scaling rash." — Diagnostic workup note