Revenue Cycle Insider

Question: We have an in-house lab, and when we bill out 87210, we charge for 2 units: one for the wet prep and one for the potassium hydroxide (KOH) slide. We have been getting many denials where the insurance companies will only pay for one. Is this correct?

AAPC Forum Participant

Answer: No — insurance should pay for the two different slide preparations. But you’ll need to follow CPT^® guidelines before will pay you.

First, some background. The test described by 87210 (Smear, primary source with interpretation; wet mount for infectious agents [eg, saline, India ink, KOH preps]) involves different ways of preparing the slide. For the wet mount, the lab mixes salt solution on a microscope slide with the contents of a vaginal swab and checks for bacteria, yeast cells, trichomonads, white blood cells that indicate infection, or “clue” cells that indicate bacterial vaginosis.

To check specifically for yeast, the lab might also prepare a KOH slide by mixing the vaginal sample with KOH in addition to the salt solution. The KOH destroys bacteria and cells from the vagina, leaving yeast hyphae and spores (if present) that indicate a yeast infection.

If the lab performs both a wet mount and a separate KOH slide, you can bill 2 units of 87210. However, CPT^® guidelines for the Microbiology subsection of the Pathology and Laboratory codes state that “For multiple specimens/sites use modifier 59.” Modifier 59 (Distinct services) indicates that the second lab interpretation is distinct from the first and should be paid separately.

Remember: Billing for Medicare is different, as Medicare recognizes two different codes for the different slide preparations: Q0111 (Wet mounts, including preparations of vaginal, cervical or skin specimens) and Q0112 (All potassium hydroxide [KOH] preparations). So, rather than billing 2 units of 87210 with modifier 59, you’ll bill 1 unit of each code when billing Medicare for the two different slide preparations.

Bruce Pegg, BA, MA, CPC, CFPC, Managing Editor, AAPC