Add-on CPT Coding

The CPT surgical pathology section borrowed the add-on definition from the CPT Coding manual’s Medicine Guidelines where they are defined as “commonly carried out in addition to primary procedure performed”.  Only four positions listed in the surgical pathology section of the CPT manual meet this criteria: decalcification (88311) and special stains (88312, 88313, and 88314). In the Pathology Service Coding Handbook, Dennis Paget extends them in the range 88311-88319 plus 88329-88372 because they always are additional to a primary surgical pathology 88300-88309. Add-ons can be interpreted more broadly as for chemical components like cooper or Zink (88318) or enzymes (88319). Actually IHC (immunoperoxidase 88342) and immunofluorescence (88346-88347) are also add-ons, although the latter might be performed for some reasons without a primary H&E study. In-situ hybridization (FISH) 88367-88368) is also not a “pure” add-on, although it can be done from a paraffin block for Hear after the primary H&E and other studies.

 In general, add-on procedures are simple in coding if certain rules were followed. They reflect the general principles of CPT coding in surgical pathology.

1.  First and foremost, there is a primary examination of the specimen by H&E slide examination. Even if a special stain, for example, is performed as a stand-alone from a block in an outside laboratory consultation.

2. The add-on procedure should be specifically defined in the pathology report and match with the list of 88311-88314 descriptors in the CPT code manual.

3. The add-on code should be connected with a certain specimen/part in the pathology report.

4. There is a certain rule of how many times the add-on procedure was reported for charge independently of how many times it was performed for the specimen/part. The amount of blocks decalcified or stained for a particular specimen/part is irrelevant to the chargeable code. Unless there are local agreements with payers even100 decalcified blocks in post chemotherapy Ewing’s sarcoma specimen is the same one code 88311 as only one decalcified block in a osteoarthritis femoral head specimen. Three blocks from lung wedge biopsy stained for AFB yield one 88312 in the same way as one block of the biopsy.

All add-on procedures have both a professional and a technical component although the principles of filing claims can be different in hospitals and independent laboratories. This billing issue is out of the scope of this manual, but because of permanent interest to this subject an addendum will be placed in the end of this Add-on article which in some degree based on excerpts from the latest edition of Dennis Paget’s Pathology Service Coding Handbook.

1. + 88311 Decalcification procedure (List separately in addition to code for surgical pathology examination)

 This is the most frequently used add-on code in surgical pathology for bone specimens from biopsies to extensive resections. Because the solely role of decalcification is to make bone section or fragment combatable in texture for paraffin embedding with following microtomy, decalcification is not used in undemineralized bone processing techniques like embedding in methyl methacrilate plastic. This circumstance should be taken into account when computer dictionary automatically assigns 88311 to bone specimen.

Bone marrow biopsies go, as a rule, with decalcification procedure, although in rare occasions, for example in a child biopsy, the biopsy core is not mineralized.

Sinus aspirates often contain bone fragments (turbinate, ethmoid) that require decalcification. Calcified heart valves, uterine leiomyomas, arterial plaques, some tumors also require decalcification. If the decalcification procedure is coded as add-on that is completely reasonable, the pathology report should reflect it with a definite statement. The decalcification procedure should be mentioned in the pathology report in a regular bone specimen as well.

It is necessary reiterate that number of decalcified bones in a particular specimen does not correspond with the number of decalcification codes for this specimen. Two blocks of sections of two femoral head specimens in one person are two 88311 codes, on the other hand numeral blocks in a tumor specimen are only one 88311 code according to rules of CPT coding in surgical pathology.

2. + 88312 Special stains (List separately in addition to code for primary service); Group I for microorganisms (e.g. Gridley, acid fast, methenamine silver), each

+ 88313 Group II, all other, (e.g. iron, trichrome), except immunocytochemistry and immunoperoxidase stains, each

 + 88314 histochemical staining with frozen section (s)

 It is reasonable to present all three add-ons together because their divide is artificial. All of them have a sign “+” attached to the numerical code as an add-on.

The list of the stains is apparently incomplete, for example the most popular H. pylori stain is not mentioned. Some of them have a dual use, for example PAS/Alcian blue can be reported as both 88312 and 88313 that require a note in the pathologist report, as evidence of specific findings that reflect relevance to the pathology diagnosis.

88314 is recommended for snap frozen tissue instead of paraffin sections as a part in muscle biopsy studies in neuropathology. Usually muscle biopsy has a general charge that is compound by many studies (up to 25 depending on the institution), including electron microscopy (88348-88349), enzymes (88319), special stains (88313,88314), and a regular H&E slide (88305).

Again, it would be a stretch to consider 88342, as well as 88360 and 88361, as pure add-ons, although technically they are. They are included in this manual with some reluctance, but they are used in the surgical pathology laboratories practice on the daily basis.

8342 Immunohistochemistry (including tissue immunoperoxidase) each antibody

This is the most popular “add-on” code in surgical pathology. “Each antibody” is the main word which determines the number of charge codes. It means detection of a specific antigen in different specimens/parts. The list of antibodies is impressive, although there are most frequently used, as Her-2/neu, Ki-67tokeratin IgA, IgG, IgM, kappa, lambda etc, etc, etc. From clinical point, there are most often used combinations of them. Sometimes a IHC “cocktail” stains like the p63/AMCAR on prostate tissue revels two antigens which a pathologist could claim as two 88342 chargeable codes, and in opposite the AE1/AE3 stain is only one 88342 chargeable code. The key issue is the presence of each antigens mentioned in the pathologist’s report (But see below!).

Again see below for 2o14!

88342 became a target of recent Medicare regulations which are presented in remarks below, including excerpts from Dennis Padget’s Pathology Service Coding Handbook.

IHC is a “breadwinner” for laboratories. Although most IHC stains detect a single antibody, “cocktail” stains can detect two or more in a simple application. This circumstance potentially can be a source of abuse by laboratories, because some “double” or “triple stain” kits present a combination of vials but each vial might detect only a single antibody. More, the staining reagent in a single vial can detect two antibodies, for example AE1and AE3, but they are undistinguishable on the slide by a pathologist and cannot be reported separately that is the key for charge coding. It means that they should be coded as 88342×1. More details at the end of the article in the Addendum.

88360 Morphometric analysis, tumor immunochemistry (e.g. Her-2/neu, estrogen receptor/progesterone receptor) quantitative or semi quantitative, each antibody, manual


88361 using computer-assisted technology

 The Pathology Service Coding Handbook specifically underlines: “Do not report 88342 in conjunction with 88360 or 88361 for the same antibody” because it is obvious that quantitative data include qualitative negative or positive reading, including estimation of intensity of reading.

Each code 88342, 88360, and 88361 has a technical component (TC) and a professional component with or without mentioned 26 modifier.

Immunofluorescence direct (88346) and indirect (88347) , Flow Cytometry of cell cycle and/or DNA ploidy analysis (88182) and for immunophenotyping tests (88184-88185 for technical component) and professional component depending on the amount of markers (88187-88189), In- Situ Hybridization – FISH for tumors quantative (88365) and morphometric analysis (88367-computer and 88368-manual), Electron Microscopy (88348,88349), and other studies are more remote from previous as a typical add-on procedure. Although they are very much stand-alone studies, technically they serve as additional examination to the basic morphological studies coded as 88302-88309. Though being part of surgical pathology laboratory, these studies are different by nature of coding and billing by adhering to a fixed billing mode. Nevertheless, they bear all principles of a regular add-on code by having technical and professional components, relating to specific antigenic or morphologic structure independently of the number of blocks or slides were performed. And the pathologist report should mention all the chargeable items for justification of the charge claim.

Addendum regarding new Medicare regulations of IHC coding/billing

Since January 1, 2012 Medicare has gone back to specimen instead of block as the basic unit of service. It has also limited the charge units for “cocktail” stains.

Excerpt from the Pathology Service Coding Handbook by Dennis Padget (the Handbook is distributed by subscription; it is in almost every medical institution which uses CPT coding):

The AMA and the CAP have always focused on the specimen in relation to IHC codes 88342, 88360 and 88361. However, from Oct. 1, 2009 through Dec. 31, 2011, Medicare via the NCCI policy manual prescribed block as the focal point. Notwithstanding, the Jan. 1, 2012 revision to the NCCI policy manual reverts to specimen as the basis for charging IHC procedures for Medicare purposes. Hence, inasmuch as all major pathology coding authorities now prescribe “each different antibody tested and reported per each different specimen (not block or level)” as the approved unit of service for the three IHC codes, there is no longer an authoritative basis for defending the use of block as the focal point, regardless of the patient source or financial class. All patients, government payers, and private insurers should now be billed based on antibodies per specimen, not block, level or any contrary unit.

This chapter in Pathology Service Coding Handbook contains useful and interesting to read discussion of IHC coding/billing issues, including examples of different approach in Medicare and private insurers billing. However, these questions are beyond the scope of the current manual.  It is a certain recommendation to obtain the Handbook at the office of the department’s billing officer for deep understanding of the ICH coding/billing principles. Unfortunately, histotechnologists who do coding/billing by themselves do not have a subscription for the Handbook.

There are changes for 2014.  See CAP documents and links:

CMS followed the AMA RUC recommendation to decrease both the TC and the PC for IHC.   The 88342 code has been replaced by two G codes (G0461 to report one unit of service per specimen and G0462 to report each additional stain.)

The decrease in reimbursement for the G0462 code as compared to the G0461 code comes predominately from the professional component (-26 modifier).


These materials do not represent official advice of the CAP, AMA, CMS or other governmental institution. The information will not bear any liability for its application and will not prevent any dispute with a third-party payer.


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