Pathology/Lab Coding Alert

Antibody and block define unit of service.

You’ve reported some special stain codes “per block” for a years, but 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody) stubbornly remained “per specimen” — until now.

CPT^® 2014 revises 88342 and adds a new code to clear up unit-of-service confusion and inconsistencies that have plagued coding for qualitative immunohistochemistry (IHC).

Greet Code Revision and Addition

Beginning Jan. 1, 2014, here are the codes you’ll use to report qualitative IHC stains:

• 88342 — Immunohistochemistry or immunocytochemistry, each separately identifiable antibody per block, cytologic preparation, or hematologic smear; first separately identifiable antibody per slide
• +88343 — … each additional separately identifiable antibody per slide (List separately in addition to code for primary procedure).

You should use these codes when your lab performs an immuno “stain.” That means the lab uses one or more antibodies that selectively bind to antigen(s), if present, in tissue or cells. “These antibody ‘stains’ create visual changes that the pathologist can use to provide a diagnosis,” explains Peggy Slagle, CPC, coding and compliance manager for the department of pathology/microbiology at the University of Nebraska Medical Center in Omaha.

The 88342/+88343 procedure is not quantitative or semi-quantitative as it is for associated codes 88360 (Morphometric analysis, tumor immunohistochemistry [e.g., Her-2/neu, estrogen receptor/progesterone receptor], quantitative or semiquantitative, each antibody; manual) or 88361 (…using computer-assisted technology).

Focus on Unit of Service

When you think about the unit of service for 88342 and +88343, three phrases from the definitions jump out at you: “each separately identifiable antibody,” “per block,” and “per slide.” Let’s break that down.

Per block: The old 88342 definition didn’t specify whether to report the service per specimen or per block. CMS policy has waffled on this point over the years, changing how you report 88342 — at least for Medicare beneficiaries. Now CPT^® 2014 takes a stand: You should report a unique qualitative antibody stain per block. Be aware that Medicare may not agree. Read the next section of this article to see how CMS currently weighs in on the issue.

If you’re dealing with cytology instead of a tissue specimen, the 88342 code revision allows you to report the code for each “cytologic preparation” or “hematologic smear.”

Per slide: Don’t let the “per slide” in CPT^® 2014 fool you. “You should never code special stains per slide,” Slagle emphasizes. Properly understood, “per slide” is actually part of the larger phrase in the code definition: “separately identifiable antibody per slide.” In other words, the unit is the separately identifiable antibody as seen on a tissue or cytology slide. That leads to the next phrase.

Each separately identifiable antibody: The old definition stated “per antibody,” but CPT^® 2014 changes the wording to “each separately identifiable antibody.” The new wording provides a much-needed clarification for IHC stains. Some of these stains involve multiple antibodies in a “cocktail,” and how you report the service depends on whether each antibody is visually distinguishable on a slide for diagnostic purposes.

For instance, a common prostate triple stain (PIN4) contains three antibodies — p504S, which stains adenocarcinoma cytoplasm red; P63, which stains basal cell nuclei brown in prostatic intraepithelial neoplasia (PIN); and CK903, which stains basal cells in benign and PIN specimens. With documentation that each of these antibody stains is “separately identifiable” on the slide, you should report 88342 and +88343 x 2, based on the CPT^® 2014 changes.

On the other hand, some multiple-antibody stains aren’t “separately identifiable,” so you should not report multiple units. For instance, an AE1/AE3 immunostain on breast tissue involves two histochemical antibodies, but functions as a single-color stain to detect the presence of cells expressing both low- and high-molecular-weight cytokeratins. “That means you should report AE1/AE3 as a single unit of 88342,” explains Dennis Padget, MBA, CPA, FHFMA, The Villages, Fla., Senior Editor in Chief, Pathology Service Coding Handbook, for American Pathology Foundation.

Beware CMS Policy Conflict

The CPT^® 2014 changes clarify the unit of service for IHC coding. But unless CMS makes big changes to its policy, you’ll have to implement a different coding scheme for Medicare patients.

Here’s the current CMS policy published in the NCCI Policy Manual, initially effective Jan, 1, 2012:

“The unit of service for immunohistochemistry (CPT^® codes 88342, 88360, 88361) is each antibody(s) stain (procedure) per specimen. If a single immunohistochemical stain (procedure) for one or more antibodies is performed on multiple blocks from a surgical specimen, multiple slides from a cytologic specimen, or multiple slides from a hematologic specimen, only one unit of service may be reported for each separate specimen. Physicians should not report more than one unit of service per specimen for an immunohistochemical antibody(s) stain (procedure) even if it contains multiple separately interpretable antibodies.”

CMS per specimen: Contrary to CPT^® 2014 code definitions that direct you to report 88342 and +88343 per block, the current NCCI Policy Manual emphasizes reporting one 88342 unit “per specimen” even if the stain is “performed on multiple blocks.”

Cocktails are 1: Also contrary to CPT^® 2014 code definitions, the current NCCI Policy Manual states that you should report just one unit of 88342 for “an immunohistochemical antibody(s) stain (procedure) even if it contains multiple separately interpretable antibodies.”

“The ‘procedure,’ according to CMS, means that if multiple antibodies are applied to the slide from a single vial, you should code just one unit of 88342, even if the pathologist separately interprets the distinct antibodies,” Padget explains.

Policies could cost you money: “It’s not unusual for pathologists to examine IHC stains on multiple tissue blocks from a single specimen, or to interpret discrete antibodies from a multiple-antibody stain,” says R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Ark.

For every 88342 you can’t claim due to the CMS policy, you stand to lose $115.34 (2013 Medicare Physician Fee Schedule National amount, conversion factor 34.023).

Watch for change: Be on the lookout to see if CMS makes a policy change to accommodate the 88342, +88343 code changes. “We may learn CMS’s decision via the 2014 Medicare physician fee schedule final rule due for release on or before Nov. 27, or through the 2014 version of the NCCI Policy Manual, which could be available as early as Dec. 1,” Padget says.

Look to future issues of Pathology/Lab Coding Alert to keep you in the know about these, and other important coding and policy changes that will affect your bottom line in the new year.