Pathology/Lab Coding Alert

Question: Our lab processed a lymph node biopsy for a patient with melanoma. We stained blocks A-E with Mart-1, and blocks A-C with Ki67. Should we bill 88342 x 8 or 88342 x 2?

California Subscriber

Answer: The answer may depend on your payer, but 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody) x 2 is the correct way to bill Medicare for this service.

Although for a time, Medicare and other insurers allowed billing immunohistochemistry (IHC) stains per block, a change to the NCCI Policy Manual effective Jan. 1, 2012 bans the practice.

Medicare's correct coding initiative (CCI) instruction states, "The unit of service for immunohistochemistry (CPT codes 88342, 88360, 88361) is each antibody(s) stain (procedure) per specimen. If a single immunohistochemical stain (procedure) for one or more antibodies is performed on multiple blocks from a surgical specimen, multiple slides from a cytologic specimen, or multiple slides from a hematologic specimen, only one unit of service may be reported for each separate specimen."

The Medicare rule clearly leaves you no option but to bill 88342x2 for your case. Your lab performed two unique IHC stains on a single specimen, and the number of blocks is not relevant for Medicare payers.

Rules vary: Other payers may still allow billing IHC per block per stain, however. Since your case involves one IHC stain on five blocks, and a different IHC stain on three blocks, payers who allow "per block" instead of "per specimen" billing would accept 88342x8 for the service you describe.