CAP TODAY letter IHC Coding Changes

CAP TODAY magazine ( published my letter IHC coding changes in the February, 2014 issue. The editor combined very skillfully my original letter to the magazine with the proposal part of my post  88342 code debacle on my Surgical Pathology Coding CookBook website’s blog, although the latter contained more details. I would appreciate your responses directly in the website’s comment section.

The copy of the CAP TODAY’s letter is below:


IHC coding changes

The January 2014 article “Advocacy pays off, though 2014 CMS cuts will sting” is a report of the impact on pathologists of the 2014 Medicare physician fee schedule and the CAP’s strategy to prevent CMS cuts on the supposedly overvalued 88342 high-volume code. It seems that a compromise still can be reached between the AMA/CAP88342/88343 per block/slide position and the CMS G0461/G0462 per specimen position. Three surgical pathology practice issues can be addressed:

Diagnostic. The definition of a specimen as a unit of service is the cornerstone of CPT coding in surgical pathology. The vast majority of coded cases are specimens. In this regard, the CMS is right. However, the AMA/CAP have a point in pursuing the block approach to IHC coding. In surgical pathology practice, there are diagnostic situations in which different blocks of the same specimen can have different recognizable antigens by antibody stain or their absence, which can have diagnostic value. These occasions, though rare and more common in   oncology, can be     coded separately or covered by a modifier. A pilot study can show how important the need to code per block can be.

Histotechnological. Although peroxidase chromogen is a stain, it only makes the presence of a specific antigen visible through an immunological reaction with a monoclonal antibody. This technology requires equipment, specific reagents, and certain skills. Due to variations in sensitivity and specificity in immunological reactions, interpretation can have subjective variations. On the other hand, the Orwellian paraphrase “All antibodies are equal, but   some antibodies are less equal” is technologically correct because working time, except reagents, is not equal. They cannot be coded for reimbursement equally.

The sticking point is that multiplex antibodies (double, three stain) can occur on the same slide. This can be addressed by a G code for this particular cocktail. A G code as an addition to the main CPT code might be a necessity because of histotechnological peculiarities.

CPT structure. In general, G codes are a sign of weakness of CPT-4 coding (the standard 88000 code system can’t be applied). The goal is to avoid a coding solution that erodes a well-established and generally satisfactory working   system. A G code can be applied only as an extraordinary coding solution. When the CMS replaced 88342 CPT codes with G0461/2 codes, it meant that CPT coding had been disregarded. However, an additional G code as a methodological adjustment is acceptable because in this situation a G code does not erode the CPT coding fabric.

The CMS’ decision regarding IHC coding and reimbursement cuts is ill-advised because it is damaging to surgical pathology as a specialty, for which dramatic cuts in pathologist fees are only part of the main problem. The solution to the problem should consider the interest of the specialty.

I suggest this compromise: The   AMA/CAP would abandon the block/slide notion of 88343 as a unit of service, but the CMS would take 88343 as each additional stain, including the same stain on a different block of the same specimen if diagnostically warranted. The multiplex stain controversy can be solved with G codes. 88343 and a G code for multiplex stain can have fee adjustments that can satisfy the need to cut costs. The integrity of surgical pathology practice would be honored, and an abuse of the system would be prevented.

Izak B. Dimenstein, MD,


Grand Rapids, Mich.

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