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Test Code M36 KOH Preparation

Important Note

For ectoparasites such as mites (scabies), lice and ticks see Arthropod Exam.

Additional Codes


PowerChart: KOH Prep

Epic: LAB251 KOH Prep

MA Cerner: KOH.

Test Method

Wet Prep with Addition of Potassium Hydroxide (KOH)

Specimen Requirement

Skin scrapings are required.

Additional Specimen Collection Information

Collect specimen using a sterile scraper [tongue depressor, scalpel or tweezers]. Sponge the infected area with 70% alcohol and allow to dry. Scrape the active [leading] edge of the lesion or top of the vesicle, with the sterile scraper, into a sterile container. Label the specimen appropriately [including source, date and time of collection]. Transport the specimen to the laboratory immediately after collection.


Performed Monday through Sunday, allow 24 hours turn-around time after the specimen is received in Microbiology.

Reference Values

Negative for Fungal Elements

(Presence or absence of fungal elements is reported.)

CPT Code Information

87220 Identification of Organism from Primary Source and Sensitivity Studies; Tissue examination by KOH slide of samples from skin, hair, or nails for fungi or ectoparasite ova or mites (eg, scabies)

Useful For

Detection of fungi elements in skin scrapings.

LOINC Code Information

55303-2 Fungus [Presence] In Skin By KOH Preparation