Quantitative/Semi-Quantitative IHC CPT Coding

Per the 2014 AMA CPT text, the following descriptions are given for CPT codes 88360 & 88361:

• 88360-Morphometric analysis, tumor immunohistochemistry (e.g., Her2neu, estrogen receptor/progesterone receptor), quantitative or semiquantitative, each antibody, manual
• 88361-… using computer-assisted technology

Notice that both 88360 and 88361 have 3 antibodies listed in the code definition but don’t think those are the only antibodies described by these codes.  Her2neu, ER, & PR are only examples of the antibodies for these codes, so 88360/88361 can be used for other antibodies.  Also, don’t be confused by the word “tumor” as labs might quantify other sources such as whole blood or plasma cells which would be reported with 88360/88361.  For example, CD34 is used to quantify positive plasma cells, 88360/88361 would be reported.   

In addition to the above mentioned antibodies, other antibodies that might be quantitative or semiquantitative are: Ki-67, p53, MART-1, CD34, and CD117 but this is not a complete list.  88360/88361 should be reported for any medically necessary quantitative or semiquantitative IHC test.

Morphometric describes something that is measured, so 88360/88361 describes IHC tests that involve counting or at least estimating the number of stain cells.  The key to identifying quantitative/semiquantitative tests is that the pathologist or automated system actually counts some of the positive stained cells or makes a visual approximation of the percentage of stained cells and documents the results using a numeric representation of their findings (ie, CD117 shows approximately 5% of positive marrow cells).

To determine if a quantitative/semiquantitative IHC is reported with 88360 or 88361the distinction is if the IHC stains were evaluated manually or using computer-assisted technology.  In other words, was the counting performed by a human or microprocessor.  For a pathologist evaluator, whether using a microscope or digital image on computer to quantify and evaluate stained cells, report 88360.  For an “automated” or “computer” microprocessor determined quantification and evaluation, report 88361. 

Per the code definition, the unit of service for 88360/88361 is per antibody.  Report a single unit of 88360/88361 per each distinct antibody, per specimen. For example, using ChromaVision Automated Imaging System, the pathologist evaluates ER, PR, Her2neu on blocks A1 & A2 from a breast lumpectomy.  Report 88361x3 as only 3 distinct antibodies were evaluated. 

Some quantitative/semiquantitative non-breast marker IHC stains are manual, some could be computer assisted.  To support the charge of 88360/88361 documentation should indicate whether the 88360/88361 was performed manually or computer-assisted.