Pathology/Lab Coding Alert

Question: How should we report our PIN4 triple stain under the revised IHC codes in 2015?

Texas Subscriber

Answer: Because there’s some variability in how labs and pathologists process the PIN4 triple stain, we’ll have to make some assumptions to answer the question. If this is a typical PIN4 in which the pathologist examines a slide stained with the multiple antibodies that the pathologist separately interprets, then you should bill this as a multiplex immunohistochemistry (IHC) stain.

For instance: If the stain involves AMACR, p63, and CK903, and each of the three stains provides unique diagnostic information as opposed to “mixing” to form a single diagnostic entity, then you can bill 88344 (Immunohistochemistry or immunocytochemistry, per specimen; each multiplex antibody stain procedure) in 2015.

Watch documentation: To support billing 88344 instead of 88342 (… initial single antibody stain procedure), the pathologist should mention the diagnostic contribution of each separate stain. 

Forget old way: Code 88344 is new in 2015. Prior to the introduction of this multiplex stain code, you had to report multiplex IHC stains using the 2014 codes (revised or deleted in 2015) 88342 (Immunohistochemistry or immunocytochemistry, each separately identifiable antibody per block, cytologic preparation, or hematologic smear; first separately identifiable antibody per slide) and 88343 (… each additional separately identifiable antibody per slide [List separately in addition to code for primary procedure]). Specifically, you would have reported the PIN4 stain as described as 88342 and 88343 x 2.