KOH mount (fungal test)
Quick answer: A KOH mount treats skin, hair, nail or discharge samples with potassium hydroxide so fungi can be seen under a microscope. It is a quick test for fungal infections such as ringworm, nail fungus or vaginal yeast.
- SampleSkin, nail or hair scraping, or swab
- TakesA few minutes
- Before the testAvoid antifungal creams and nail polish on the area before the test if your doctor agrees.
How the test is done
- 1A small scraping is taken from the skin, nail or hair
- 2The sample is placed on a glass slide
- 3A drop of potassium hydroxide dissolves the skin cells
- 4The slide is checked under a microscope for fungal threads or yeast
What your results can mean
Reading your report
A negative result does not fully rule out fungal infection, and a culture may be added.
If the result is outside the usual range
Seeing fungal threads or yeast cells can point to infections such as ringworm, nail fungus or candida. A negative result does not rule out a fungal infection, as fungi may be missed.
Who usually has this test
People with itchy, scaly or ring-shaped rashes, thickened nails, or white vaginal discharge.
Risks and aftercare
The scraped area may feel slightly sore.
Names and options
Also called: KOH preparation, KOH stain, fungal scraping, potassium hydroxide test
Options
- Skin, hair or nail scraping
- KOH preparation
- Fungal (KOH) stain
Listed by the hospital as
- FUNGAL SCRAPING BY KOH PREPARATION
- KOH PREPERATION
- FUNGAL (KOH) STAIN
Questions about this test
Does a KOH test hurt?
Skin or nail scraping usually causes only mild discomfort. No needles are used.
Can the KOH mount find the type of fungus?
No, it shows that fungi are present but not the exact species. A fungal culture is needed for that.
Is KOH used for vaginal discharge?
Yes, adding KOH helps show yeast, and a fishy smell when it is added suggests bacterial vaginosis. It is a simple, quick check.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.