Pathology/Lab Coding Alert

Question: Our pathologist performed a concentrated (cytospin) pleural fluid smear exam. The work included Mucin and PAS-D stains as well as the following IHC tumor markers: CD-15, EMA, CEA, GCDFP-15, calretinin, CK-7, CK-20 and AE1/AE3. The pathologist's diagnosis was -malignant cells present, consistent with metastatic carcinoma from mammary primary.- How should we code the pathologist's work? 


Missouri Subscriber

Answer: For the cytospin and subsequent smear exam of concentrated pleural fluid, report 88108 (Cytopathology, concentration technique, smears and interpretation [e.g., Saccomanno technique]). The stains you listed represent special stains, and you should code each separately.

For the Mucin and PAS-D stains, report +88313 x 2 (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). This is an add-on code that you should list in addition to the primary service, which is the 88108 cytopathology. Although the special stain codes are in the surgical pathology section, you are not limited to reporting them for tissue specimens.

The pathologist also evaluated eight immunohistochemistry (IHC) stains: pan cytokeratin (AE1/AE3), calretinin, carcinoembryonic antigen (CEA), CD-15, cytokeratin 7 (CK-7), cytokeratin 20 (CK-20), epithelial membrane antigen (EMA), and gross cystic disease fluid protein 15 (GCDFP-15). You should report each of these IHC stains separately, meaning that you will indicate 88342 x 8 (Immunohistochemistry [including tissue immunoperoxidase], each antibody). The 88342 description says, -each antibody,- so you should reportmultiple units of the code if the lab performs more than one antibody stain on a single specimen.

Even if the pathologist uses an IHC -antibody cocktail- -- a single stain that contains multiple histochemical antibodies -- you should separately code each different-color antibody that the pathologist sees and assesses individually.

Exception: Count the AE1/AE3 as a single 88342 because the two histochemical antibodies provide a single-color stain to detect the presence of cells expressing both low- and high-molecular-weight cytokeratins.