Pathology/Lab Coding Alert

Question: We are a dermatopathology lab with a Mohs surgeon on staff who has a separate CLIA number. We have two scenarios that I don’t know how to bill:

1.     The Mohs surgeon takes a skin biopsy and a separate pathologist performs a frozen section exam and a specimen exam under our lab’s CLIA number.

2.     The Mohs surgeon performs Mohs and diagnoses differential BCC. He submits a block to a pathologist to confirm diagnosis. Can we bill 88323 or 88305 using our CLIA number?

Texas Subscriber

Answer: In your first example, you can bill 88331 (Pathology consultation during surgery; first tissue block, with frozen section[s], single specimen) and 88305 (Level IV - Surgical pathology, gross and microscopic examination, Skin, other than cyst/tag/debridement/plastic repair) under your CLIA number. The surgeon will bill a biopsy code, such as 11643 (Excision, malignant lesion including margins, face, ears, eyelids, nose, lips; excised diameter 2.1 to 3.0 cm)  because he doesn’t perform Mohs on that date.

In your second example, the surgeon should bill a Mohs code (17311-+17315 (Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain[s] [e.g., hematoxylin and eosin, toluidine blue] …) under his CLIA number.

You cannot bill anything under your CLIA number. You cannot use the outside consultation codes such as 88323 (Consultation and report on referred material requiring preparation of slides). Because you stated that the Mohs surgeon is part of your department, using the codes for consultation on referred slides or material (88321-88325) would not be appropriate under any circumstances.

Nor can you bill a surgical pathology code such as 88305 or 88331. Correct Coding Initiative (CCI) edits are in place to prevent billing Mohs with 88331 or 88305, which amounts to billing the pathology twice. You can override the edits with modifier 59 (Distinct procedural service) in some circumstances, such as if the surgeon removes a biopsy and requests your diagnosis before performing Mohs. In that case, your 88331 and/or 88305 service is for a biopsy, and the surgeon performs his own pathology on the Mohs excisions.