Pathology/Lab Coding Alert

Question: Suspecting a vaginal infection when a patient presents for a Pap test, the physician sends two vaginal swabs to the lab. We prepare a wet mount from one swab and KOH slide from the other. How should we code this?

Michigan Subscriber

Answer: You can report two units of 87210 (Smear, primary source with interpretation; wet mount for infectious agents [e.g., saline, India ink, KOH preps]) because the lab performed two different slide preparations.

A wet mount involves mixing a salt solution on a microscope slide with the contents of a vaginal swab to check for bacteria, yeast cells, trichomonads, white blood cells that indicate infection, or other cells that indicate bacterial vaginosis.

Labs use a KOH prep to check specifically for yeast. The procedure involves adding potassium hydroxide to the salt solution with the vaginal swab on a slide, destroying bacterial and vaginal cells but leaving fungal hyphae and spores, if present. Positive KOH results indicate a yeast infection.

Distinguish KOH codes: CPT provides another KOH code, but you should not use it for vaginal swabs -- 87220 (Tissue examination by KOH slide of samples from skin, hair, or nails for fungi or ectoparasite ova or mites [e.g., scabies]).

Medicare is different: For a Medicare beneficiary, you-ll have to use Q0111 (Wet mounts, including preparations of vaginal, cervical or skin specimens) or Q0112 (All potassium hydroxide [KOH] preparations).