Pathology/Lab Coding Alert

Question: We received a 3.2 cm scalp lesion excision, which the pathologist diagnosed as cutaneous melanoma with a Breslow thickness of 3.3 mm. The surgeon also submitted a superficial suboccipital lymph node identified as a sentinel node through methylene blue drainage. The pathologist processed the node in two blocks, cutting serial thin sections from three levels in each block for staining with H&E, S-100, and Melan-A to identify micro-metastases. How should we code this?

Missouri Subscriber

Answer: You should report the pathology exam of the excised skin lesion as 88305 (Level IV - Surgical pathology, gross and microscopic examination, … Skin, other than cyst/tag/debridement/plastic repair …). Sentinel lymph node biopsies require additional resources and work beyond a typical lymph node biopsy, so you should select 88307 for a sentinel node instead of 88305 (… lymph node biopsy).

You list three stains for the sentinel lymph node biopsy that you should account for in your billing. The hematoxylin and eosin (H&E) is a standard tissue stain for pathology specimens, so that’s included in the 88307 charge.

The S-100 and Melan-A stains are special immunohistochemistry stains that you should separately report. For this case, you should bill 88342 (Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain procedure) for the S-100 stain and +88341 (…each additional single antibody stain procedure (List separately in addition to code for primary procedure)) for the Melan-A stain.

Watch units: Although the pathologist processes and examines many slides with these two antibody stains (multiple slides from three sections of two blocks), you should report just one unit of 88342 and one unit of +88341. That’s because the stated unit of service for these stains is “per specimen.”