88343 vs. G0462

AMA’s 88343 block vs. CMS’s G0462 specimen

Immunohistochemistry (IHC) has become the dominant methodology in histotechnology. At the 2013 National Society of Histotechnology (NSH) Convention, almost all 22 IHC out of 127 total workshops were sold out. Machinery and reagent suppliers’ vendor booths (Ventana, Dako) were the largest at the Convention’s trade show. Demand and supply are parallel processes. The cost of surgical pathology diagnostic services steadily increases in parallel with IHC methodology implementation.

Starting on January 1th, 2014, the American Medical Association (AMA) presented in the AMA’s CPT-2014 Codebook the set of IHC codes, which are different from the Centers for Medicare & Medicaid Services (CMS) provisions. AMA’ CPT-2014 suggested 88342 code for each separately identifiable antibody per block/cytology/smear and 88343 for each additional separately identifiable antibody per slide. CMS abandoned CPT coding for Medicare claim filing for qualitative immunohistochemistry. Instead CMS suggested two G codes, namely G0461 for immunohistochemistry or immunocytochemistry per specimen and G0462 for each additional single or multiplex antibody stain. See diagram visualization on our “Surgical Pathology CPT Coding CookBook” website blog’s post  “Changes in IHC coding in 2014” (http://surgpathcode.com/?p=242)

The difference between specimen and block is the key issue in the CMS and the AMA approaches. After almost five years of vacillating between specimen vs. block, the AMA created this ambiguity. Before October 1, 2009, both the AMA and the CMS have advised that ‘specimen’ is the appropriate unit of reporting IHC for 88342 code. Between 2009 and 2012, the CMS switched to ‘block’. Who had advised the CMS? Were both coding authorities, the AMA and the CAP, able to be neutral in the CMS’s decision? On January 1, 2012, the CMS returned to ‘specimen’, but now the AMA is suggesting ‘block” as a unit of service for IHC coding. The CAP’s STATLINE (December 5, 2013, Vol. 29, Number 24) has a paragraph in an article “2014 Anatomic Pathology Code Revaluations”, which states: “Moving forward, the CAP will work with the AMA and other groups to pressure CMS to change their G code definitions so that payment is made per slide’ rather than ‘per specimen.” http://www.cap.org/apps/cap.portal?_nfpb=true&cntvwrPtlt_actionOverride=/portlets/contentViewer/show&_windowLabel=cntvwrPtlt&cntvwrPtlt%7BactionForm.contentReference%7D=statline/index.html&_state=maximized&_pageLabel=cntvwr .  Is not this a coding mess?

Although the AMA has a point that in some occasions, especially in oncology surgical pathology, ‘block’ reflects the unit of service for IHC coding, the CMS’s adherence to ‘specimen’ is more reasonable in many aspects. First, the main CPT coding principle in surgical pathology is ‘specimen’ as unit of service, although it is explicitly mentioned only for 88300-88309. Second, ‘specimen’ is simpler for account (CPT coding is for billing and only for this purpose). Third, block/slide antibody separate multiplex reporting can generate abuse by some laboratories.

 G- codes expansion in surgical pathology is not a positive trend in coding because it is a deviation from well-established, in general rational, AMA’s CPT coding manual (See the post G0461/G0462 damage to CPT coding on our “Surgical Pathology Coding CooBookhttp://surgpathcode.com/?p=348) . In the case of G prostate biopsies codes the reason might be changes in methodology (saturation); in IHC coding, it is a result of AMA/CAP’s inability to come up with a compromise that would satisfy CMS’s goal to limit health care costs. G codes’ “contamination” erodes the CPT coding numeric system and brings additional problems to the institution’s LIS.

88342 and G0461 are very much similar except per block/per specimen difference. The 88343 code’s “each separately interpretable antibody” descriptor, however, looks as a semantic trick that generates coding ambiguity. Today “multiplex antibody stain” (double stain as the histotechnologists call them) reveals two or three antibodies. Who knows how many multiplex antibodies the technology will offer tomorrow?

 Current Procedural Terminology (CPT) coding provisions follow the basic logic of laboratory procedures. From this standpoint, the understanding dictates a rational notion. If a specimen’s presentation on the block/ cytology preparation/smear by a stain from one vial reveals a single or n+1 antibodies (or zero antibodies-negative), it is one CPT code and subsequently one charge. Would the simultaneous PAS stain of mucin and fungi coded for both 88312 and 88313? To take AMA/CAP logic to the extreme, if a histochemistry procedure (e.g. Gomori’s modification) for pancreas islands reveals countable alpha and beta-cells, there would be two charges. By the way, this procedure is not less  technically sophisticated than the immunoperoxidase stain. What about the latter that is now used for alpha beta cells studies? However, interpretation of the immunological reaction by the pathologist is more subjective and tends to be more variable do to variants in sensitivity and specificity of the reaction. Coding should not to tolerate ambiguity. Procedural considerations – not the results of the procedure- should determine laboratory coding. There should be some compromises, especially in the multiplex stain on the same slide.

The similarity of codes 88342 and G0461 might generate the notion that G0462- each additional single or multiplex antibody stain (rejection of 88343!) is superfluous and can be deactivated. However, the key provision is in the parentheses: “(List separately in addition to code for primary procedure)”. The CMS wants to know what procedure is primary and what is additional in order to lower reimbursement for additional stains.

Actually, CMS keeps the principle of payment for qualitative immunohistochemistry testing the same as it is today, but the actual reimbursement cut is significant. The table below also from the STATLINE article reflects CMS’s intentions.

CPT Code


88342 2013 Total Payment

2014 Total Payment

Total % Change from 2013 88342

G0461   $115.34 $88.04 -24%
G0461 TC $73.15 $57.39 -22%
G0461 26 $42.19 $30.65 -27%
G0462   $115.34 $68.08 -41%
G0462 TC $73.15 $55.61 -24%
G0462 26 $42.19 $12.48 -70%


Our website tries to avoid the submersion in the payments issues, but coding is about payments. G0462 Modifier 26 -70% cut is impressive. It is doubtful that CMS will abandon this code.

The G0462 code might also diminish the amount of additional antibody stains, which sometimes reach up to five to eight or even more. I’ve read about up to 10-12, even 25 that is doubtful. In most cases, pathologists do not order multiple additional stains simply to drive up costs. The main reason for “just in case” orders is diagnostic insecurity accompanied by the reluctance to answer trial lawyers’ questions about IHC testing that was not done. Tort reform is still a remote project.

All materials about IHC coding changes are presented in full in Dennis Padget‘s Pathology Service Coding Handbook and the Subscriber Special Bulletins. An excerpt from one of them is on the HistoNet discussion group http://lists.utsouthwestern.edu/mailman/listinfo/histonet  on 12/18/13. Dennis Padget’s nuanced approach is invaluable for understanding differences in reimbursement policies of different insurance entities. Many institutions have this publication.

The issue of 88342 vs. G0462 with a suggestion of a compromise is presented in the post 88342 code debacle on our “Surgical Pathology Coding CookBook” website’s blog http://surgpathcode.com/?p=352  . There is a necessity to present IHC coding as a surgical pathology specialty problem. This can lay ground to the CMS’s reconsideration of the reimbursement.

For 2015 unfortunately, the confusion that is feeding numerous interpretations and consultants remains: For non-Medicare it is per block – CPT code 88342. And of course, 88343 for multiple stains on the same slide, when the first is 88342 and additional 88343, for example in prostate triple stain (PIN4 cocktail).
For Medicare – per specimen. G0461 for the first antibody and G0462 for each additional different antibody.


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