Wiki IHC staining confusion (88342, 88344) - please help!


Pulaski, WI
Best answers
Could someone please help me with this? The pathology report supports ONE specimen. The report states "IHC stains are performed with appropriate controls & reveal strong & diffuse positivity for CK5/6, CALRETININ, & WT-1 (Nuclear). Focal positive staining is seen for CK 7, MOC31, & BEREP4. The tumor cells are negative for TTF-1, NAPSIN-A, CEA & CDX-2." The provider is billing CPT 88342-26 (4 units) and CPT 88344-26 (3 units) for the IHC staining. This doesn't seem correct to me.
This is the lay description from Encoderpro:

"This immunohistochemistry procedure, also referred to as immunostain or peroxidase-antiperoxidase (PShowAP), identifies specific antigens found in tumor cells. It is used primarily for the diagnosis of poorly differentiated neoplasms. There are several methods of performing immunocytochemistry tests; however, all involve treating the specimen with a tumor specific antibody, incubation, and subsequent washing of the specimen to remove unbound antibody and counterstaining with secondary antibodies to determine the antibody location. The specimen is examined for positive and negative responses. Multiple immunostains are normally performed on each specimen to more specifically identify the suspect neoplasm by providing known positive and negative responses specific to that neoplasm. Report 88342 for the initial single antibody identified; 88341 for each additional single antibody; and 88344 for each multiplex antibody identified."

Perhaps that will help?
If it's one specimen, then there can't be a charge for multiple units of 88342. Subsequent single antibody stains would be 88341. As I'm sure your are aware, based on the documentation, there is no way to know which stains were single antibody and which were multiplex. From my experience, some labs do particular multiplex stains as a matter of standard and then the pathologist doesn't necessarily need to indicate it was by multiplex, however, you need to know which were single and which were multiplex. You will need to check with the pathologist or someone in the lab.
Thank you both for your responses. I was aware of the Encoder description & fact that CPT 88342 should only be reported with ONE unit since there is only 1 specimen. I guess my main question was the billing of CPT 88344 (3 units). Since the report doesn't specifically state that any "multiplex antibody stains" were sounds like this code is NOT supported. If I'm reading the report correct, it seems there were 10 separate IHC stains used, so I'm thinking correct coding would be CPT 88342 (1 unit) & CPT 88341 (9 units)??? If anyone has any additional thoughts, it's much appreciated.