There are three categories in Surgical pathology.
1. IMMUNOHISTOCHEMISTRY / IMMUNOCYTOCHEMISTRY STAINS (IHC)
2. IN SITU HYBRIDIZATION (I.E. FISH)
3. MORPHOMETRIC ANALYSIS
AMA has completely revised the coding for IHC, FISH and morphometric analysis stains for 2015.
For IHC stains, the unit of service has been reversed back to per specimen (NOT per block), per single antibody stain procedure and additional codes have been introduced for each version of stains performed in this section.
The codes are setup to represent the first single antibody stain procedure (CPT 88342) and then followed with a code for each additional single antibody stain procedure (88341 CPT code description).
NOTE that CPT 88341 has a + sign denoting it is an add on code and can only be billed when CPT 88342 is also billed. Also note that the add on code in this instance is before the primary procedure code in number.
AMA didn’t have an available code in this area to make the add on code come after the primary code in number like they normally do. So coders will have to pay CLOSE attention to make sure they don’t bill the wrong code as the primary and add on code.
Finally, new codes to represent multiplex antibody stain procedure have been introduced (CPT 88344) to represent when a stain procedure contains multiple antibodies on that single stain procedure.
CPT Code: CPT 88341
Code Description: mmunohistochemistry or Immunocytochemistry, per specimen; each additional single antibody stain procedure (List separately in addition to code for primary procedure)
Use CPT 88341 in conjunction with CPT 88342. For multiplex antibody stain procedure, use CPT 88344
CPT Code: CPT 88344
CPT Description: mmunohistochemistry or Immunocytochemistry, per specimen; each multiplex antibody stain procedure
Do not use more than one unit of CPT 88341, CPT 88342, CPT 88344 for each separately
identifiable antibody per specimen.
Do not report CPT 88341, CPT 88342, CPT 88344 in conjunction with CPT 88360, CPT 88361 unless each procedure is for a different antibody.
When multiple separately identifiable antibodies are applied to the same specimen [ie, multiplex antibody stain procedure], use one unit of CPT 88344.
When multiple antibodies are applied to the same slide that are not separately identifiable, [eg, antibody cocktails], use CPT 88342, unless an additional separately identifiable antibody is also used, then use CPT 88344.
These new guidelines will once again require pathologist/laboratories to clearly document when a multiplex/cocktail stain procedure has been performed. The terms “single antibody stain procedure,” and “multiplex antibody stain procedure,” will play a vital part in the units of service as well as the code(s) that are selected.
Using the term single stain procedure indicates that the same stain that may contain multiple different antibodies in that stain must be assigned the code associated with multiplex stain procedure.
It is the procedure that also determines the unit of service of that multiplex stain. If all of the stained antibodies are performed in one single staining procedure, then you must consider that one unit of service for that multiplex stain.