A KOH lab test is a simple dermatological (skin) test used to determine if a skin, hair, or nail infection is caused by a fungus. KOH stands for potassium hydroxide.
How the KOH Test Works
The procedure involves placing a sample of the affected skin, hair, or nail on a microscope slide. A drop of potassium hydroxide (KOH) solution is then added. The KOH dissolves non-fungal elements, leaving fungal elements (if present) visible under a microscope. This makes it easier to identify fungal structures like hyphae and spores.
Why is the KOH Test Performed?
The KOH test is performed to diagnose various fungal infections, including:
- Ringworm (Tinea): A fungal infection of the skin, hair, or nails.
- Athlete's Foot (Tinea Pedis): A fungal infection of the feet.
- Jock Itch (Tinea Cruris): A fungal infection of the groin.
- Nail Fungus (Onychomycosis): A fungal infection of the nails.
- Yeast Infections (Candidiasis): While usually diagnosed differently, a KOH test may sometimes be used to examine skin scrapings.
What to Expect During a KOH Test
The procedure is quick and straightforward:
- Sample Collection: A healthcare provider will scrape a small sample of skin, hair, or nail from the affected area.
- Slide Preparation: The sample is placed on a microscope slide.
- KOH Application: A drop of KOH solution is added.
- Microscopic Examination: The slide is examined under a microscope for evidence of fungal elements.
The results are typically available within a few minutes.
Importance of Accurate Diagnosis
An accurate diagnosis of a fungal infection is crucial for appropriate treatment. The KOH test helps distinguish fungal infections from other skin conditions that may have similar symptoms, ensuring the correct antifungal medication is prescribed.
