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Pathology/Lab Coding Alert

Use These 4 Tips for Reporting New and Revised IHC Codes

Published on Sun Mar 06, 2005

Lab method and results determine your code selection

CPT 2005 changes the way you report tissue immunohistochemistry (IHC) exams. But you can always choose the right code - 88342, 88360, or 88361 - as long as you know whether the test is qualitative or quantitative/semiquantitative, and whether the procedure is manual or automated.

The code changes also clear up some previous problems, like how to overcome National Correct Coding Initiative (NCCI) edits that had stopped your lab from capturing certain quantitative/semiquantitative IHC services.

Use the following four tips to help you select the appropriate IHC code every time:

1. Decide Whether the Test Is Qualitative

Only one code describes a qualitative tissue IHC stain-CPT 88342  (Immunohistochemistry [including tissue immunoperoxidase], each antibody). Pathologists use these qualitative antibody stains as "markers" for the presence or absence of specific antigens used to identify tumor type. "The pathologist interprets these stains as 'yes,' the antigen is present, or 'no,' the antigen is not present, or may qualify based on stain intensity, without any quantification regarding the degree of staining," says Joan Logue, BS, MT-ASCP, principal with Health Systems Concepts Inc. in Longwood, Fla.

Don't overlook: The code definition states "each antibody," so you should report one unit of 88342 for each antibody stain that the pathologist examines for a specific tissue specimen. "It's not unusual for a pathologist to evaluate a series of IHC antibody stains to assist in tumor typing, and you should list each stain as one unit of 88342," Logue says.

On the flip side, don't report multiple units of 88342 for a single type of antibody stain on a single tissue specimen - even if the pathologist examines multiple slides. "A sentinel lymph node biopsy might include multiple cytokeratin-stained slides taken from various levels of the excised tissue, but the exam only involves one antibody," Logue says. You should report this service as 88307 (Level V - Surgical pathology, gross and microscopic examination, sentinel lymph node), plus 88342 for the multiple cytokeratin stains.

Lesson: Only use 88342 to describe a qualitative test, such as an estrogen receptor/progesterone receptor (ER/PR) stain that the pathologist examines to identify the presence or absence of ER/PR in a breast tissue biopsy.

If the pathologist provides a quantitative/semiquantitative ER/PR evaluation, don't use 88342. CPT 2005 revised the text note following 88342 to direct coders, "For quantitative or semiquantitative IHC, see 88360 or 88361." That's why you need to study Tip 2:

2. Document the Test as Quantitative or Semiquantitative

CPT 2005 added new code 88360. Now you have to choose between two codes that describe morphometric analysis of IHC - stained slides with a quantitative or semiquantitative result:

  •  88360 - Morphometric analysis, tumor immunohistochemistry (e.g., Her-2/neu, estrogen receptor/progesterone receptor), quantitative or semiquantitative, each antibody; manual
  •  88361 - ... using computer-assisted technology.

    "Morphometric analysis involves counting cells from sections of the slide and reporting the results as either a numerical percentage or as an approximate numerical percentage rated on a semiquantitative scale," says Christian Hansen, MD, pathologist with Northwest Hospital Center in Randallstown, Md.
     
    Hidden trap: Not every ER/PR assay is an 88360 or 88361. Although the code definitions include ER/PR as an example, you should only use these codes if the assay involves morphometric analysis and a quantitative or semiquantitative result.

    When the pathologist only identifies the presence or absence of these antigens, as in the example in Tip #1 above, you should use 88342 for the service, even though CPT lists ER/PR as an example for 88360 and 88361.

    Example: The pathologist examines Her-2/neu breast tumor slides and reports a Her-2/neu score (0-3+). "The guideline for interpreting Her-2/neu requires a combined quantitative and qualitative assessment - of the percentage of cells stained as well as pattern and intensity of staining - to determine the interpretive score. Reporting this service as 88360 is in accordance with the code definition, because the evaluation includes a quantitative assessment," Hansen says.

    Medicare and the College of American Pathologists (CAP) have published information that you might find confusing, about how to code tests such as Her-2/neu reported with a scoring system of 0, 1+, 2+, 3+. See "Be Sure You Reserve 88342 for Qualitative IHC" later in this issue for strategies to resolve this coding challenge.

    NCCI Edits - Problem Solved

    Before CPT 2004 and 2005 introduced 88360 and 88361, you may have reported this morphometric analysis of Her-2/neu breast-tumor slides as 88342 plus 88358 (Morphometric analysis; tumor).

    But an April 2003 NCCI edit disallowed this code pair, leaving labs no way to distinguish between qualitative and quantitative or semiquantitative IHC exams. "Adding 88360 and 88361 allows you to report IHC morphometric analysis with these codes, leaving 88342 only for qualitative exams," Logue says. 

    Don't miss: Notice that whether the test is semi-quantitative or quantitative doesn't distinguish between 88360 and 88361. To understand when you should select one of these codes for IHC morphometric analysis such as a Her-2/neu breast-tissue exam, you need to know Tip 3:

    3. Determine Method - Manual or Computer-Assisted

    To assign the correct IHC morphometric analysis code, you have to know if the pathologist performed the microscopic exam and count manually, or if the pathologist used computer-assisted technology.

    In the preceding Her-2/neu breast-tissue example, if the pathologist had examined the slide and selected areas for analysis by ChromaVision Automated Cellular Imaging System (ACIS) rather than counting the slide manually, the proper code for the service would be 88361. "You should report 88361 for automated IHC morphometric analysis, and 88360 for morphometric analysis performed by the pathologist's direct quantification of the IHC stained slides," Logue says.
      
    Opportunity: CPT 2005's addition of 88360 allows your lab to get complete Medicare pay for manual-scoring IHC morphometric analysis, which you couldn't do last year.

    Although the 2004 definition of 88361 did not distinguish between manual and automated morphometric IHC analysis, CMS reserved 88361 for exams using"computer software analysis of stained microscopic slides." That statement left coders to report quantitative IHC performed manually as 88342, or perhaps 88358 (Morphometric analysis; tumor [e.g., DNA ploidy]) for Medicare beneficiaries. "Now you can report manual morphometric IHC analysis as 88360 for Medicare and other payers alike," Logue says.

    4. Don't Double-Dip With 88342

    Before performing morphometric analysis, the pathologist first analyzes IHC-stained slides against reference positive and negative samples to determine if the slide warrants further quantitative or semiquantitative examination. That doesn't mean you should report 88342 for the initial look, as well as 88360 or 88361 for the morphometric analysis. "Codes 88360 and 88361 include the IHC staining and the initial, qualitative slide examination, as well as the quantitative morphometric analysis service" Logue says.

    CPT 2005 added a text note following 88342 to ensure proper coding: "Do not report 88342 in conjunction with 88360 or 88361 for the same antibody."

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