Pathology/Lab Coding Alert

Question: One of our dermatopathologists uses a Melan-A immunohistochemistry stain with an azure B counter stain. Should we bill this as one stain or two?


Tennessee Subscriber


Answer: You should bill the Melan-A as CPT 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody). In general, you should only bill specific stains when the pathologist individually visualizes and evaluates the stain to provide specific diagnostic information. When the lab uses a counter stain to improve visualization of the diagnostic stain, you should not separately bill the counter stain.

In your case, the dermatopathologist may use Melan-A immuno-stain to evaluate melanoma. Because the slides may contain many heavily-pigmented melanophages that obscure the immuno-stained melanocytes, the lab may use azure B as a counter stain. The azure B stains the negative melanophages and melanin blue-green, leaving only the melanocytes stained with Melan-A a brown color.

Because the dermatopathologist uses the counter stain only to help visualize the diagnostic Melan-A stain, not as a diagnostic tool itself, you should not separately report the azure B as a special stain (88313, Special stains [list separately in addition to code for primary service]; Group II, all other, [e.g., iron, trichrome], except immunocytochemistry and immunoperoxidase stains, each).