What is a potassium hydroxide (koh) test and what specific nursing actions should be taken when obtaining fungal skin specimens?

The potassium hydroxide (KOH) test is a test for fungal infections of the skin. The affected skin is sampled by scraping it off then KOH is added to the glass slide before taking a look at it in the microscope. The KOH dissolves epidermal tissue but does not affect the fungal tissue, leading to direct visualization of the fungal morphology.

The correct way of collecting a specimen for KOH test is first to collect the specimen using a wooden tongue depressor or the back of the scalpel blade, then placing it inside a plastic container to be sent to pathology laboratory. In cases wherein KOH microscopy is inconclusive, a fungal culture is needed and a punch biopsy of the affected area is warranted.

Specimens should be labeled by the patient's name, age, specimen, and diagnosis to prevent any mishaps in the laboratory.