Pathology/Lab Coding Alert

Question: Our pathologist examined a skin and toenail excision specimen to rule out suspected subungual melanoma. To distinguish the condition from toenail fungus, the pathologist also used a KOH slide preparation test. How should we code this?

Ohio Subscriber

Answer: For the pathologist’s gross and microscopic examination of the skin and nail specimen for melanoma, you should report 88305 (Level IV - Surgical pathology, gross and microscopic examination … Skin, other than cyst/tag/ debridement/plastic repair…). You should additionally report the KOH preparation for fungus as 87220 (Tissue examination by KOH slide of samples from skin, hair, or nails for fungi or ectoparasite ova or mites [e.g., scabies]).

Medicare: If this is a Medicare patient, you may need a different code for the KOH preparation. You might use Q0111 (Wet mounts, including preparations of vaginal, cervical or skin specimens) or Q0112 (All potassium hydroxide [KOH] preparations) depending on the payer and lab method. Consult your MAC for details.