CMS institutes new changes to IHC coding


By Dirk Elston, MD, FAAD

As of Jan. 1, 2014, Centers for Medicare and Medicaid Services (CMS) has deemed CPT codes 88342 and 88343 “not valid for Medicare purposes" when billing for qualitative immunohistochemistry (IHC) and will deny payment if billed on a claim.

Instead, Medicare has created codes G0461 and G0462 specifically for their use. To report a professional, technical, or global charge for qualitative IHC testing for a Medicare beneficiary on and after Jan.1, 2014, you must use the appropriate HCPCS Level II code with the appropriate modifier where applicable:

  • G0461 Immunohistochemistry or immunocytochemistry, per specimen; first single or multiplex antibody stain;
  • +G0462  each additional single or multiplex antibody stain (List separately in addition to code for primary procedure)

Currently, CMS pays for just one unit of service for IHC cocktail stains. With the new directive, CMS is now indicating that IHC should be billed based on the primary stain, not on the basis of the number of individual antibodies that can be detected and analyzed using that stain. For example, Medicare can be billed for one unit of G0461 for a PIN-4 IHC cocktail applied to one prostate biopsy specimen, even though the report may give a result for each of the three separately interpretable antibodies that make up the primary cocktail stain (one vial).

According to the current work descriptor, one unit of G0461 can be billed for the first qualitative IHC stain for a given tissue specimen. If you perform one qualitative IHC stain on a specimen which then results into two, three or more additional qualitative IHC stains from that specimen, each such additional stain will be reported as one unit of G0462.

More information on billing for qualitative IHC stains can be found at

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