Test Details: Fungal smear test is clinically known as KOH test. Few fungal diseases can be diagnosed clinically; most are diagnosed by isolating and identifying the infecting fungus in the clinical laboratory. The KOH (Potassium hydroxide) procedure is a method used to examine specimens for yeast. KOH serves as an enzymatic agent that breaks down debris in a specimen, such as epithelial cells and WBCs, to view yeast or pseudohyphae.