Pathology/Lab Coding Alert

Question: Our pathologist uses an antibody "cocktail" stain for prostate biopsies called p63/AMACR. How should we code the stain? Iowa Subscriber Answer: AMACR and p63 are immunohistochemistry stains. AMACR is an enzyme called alpha-methylacyl CoA racemase that shows "overexpression" in prostate cancer tissue. Pathologists use p63 -- a high-molecular- weight cytokeratin stain -- because it helps to identify basal cells that occur in normal glandular tissue but are absent in prostatic adenocarcinoma. Because the p63/AMACR cocktail uses these two distinct stains that the pathologist separately visualizes and interprets, you can code for each stain. That means you should report two units of 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody). Exception: If the pathologist uses an immunohistochemistry stain containing multiple antibodies but cannot microscopically distinguish the different stains, you should bill only one unit of 88342.