Pathology/Lab Coding Alert

Counting and computers are key.

Don’t spend all day trying to get your quantitative/semiquantitative immunohistochemistry (IHC) coding right. Just read our five expert tips to learn how to avoid the most common mistakes, and you’ll be able to leave the lab early today. 

Read on to make sure you know how to correctly use the following two codes: 

• 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.

Tip 1: Make an Example of Listed Antibodies

You’ll notice that both 88360 and 88361 list three antibodies in the code definitions: Her-2/neu, estrogen receptor (ER), and progesterone receptor (PR). But don’t make the mistake of thinking those are the only antibodies described by these codes. 

Notice ‘e.g.’: Whenever you see ‘e.g.’ — which means “for example” — in a code definition you know it’s just that — an example. You should also use 88360 and 88361 for antibodies other than ER, PR, and Her-2 neu.

Don’t get confused by the word, “tumor” in the code definition, either. Labs might quantify IHC stains on other sources such as whole blood or plasma cells, and you can still use 88360 or 88361.

For instance: CD138 may be used to assess B cell lymphoid leukemia. “We wondered if we could use either 88360 or 88361 for quantifying CD138 positive plasma cells,” says Charlotte Nicholas, director of billing and compliance for Molecular Pathology Laboratory Network, Inc., in Maryville, Tenn. 

The answer is yes. “In fact, you should use 88360 or 88361 to report any medically-necessary quantitative or semi-quantitative IHC test that a physician orders,” says Peggy Slagle, CPC, coding and compliance manager for the department of pathology/microbiology at the University of Nebraska Medical Center in Omaha.

Coder tip: In addition to the antibodies already mentioned, you might also see quantitative or semiquantitative IHC tests ordered for other antibodies such as Ki67, p53, MART-1, kappa, lambda, CD34 and CD117. Note that this list is not exhaustive.

Tip 2: Avoid the Semiquantitative Trap

“Morphometric” describes something that is measured, so it comes as no surprise that 88360 and 88361 describe IHC antibody tests that involve counting or at least estimating the number of stained cells. You might see the result listed as a percentage, or possibly as a score.

Pitfall: Some coders think that all scoring systems are qualitative, but that might not be the case. The key to identifying quantitative or semiquantitative tests that warrant reporting 88360 or 88361 is that the pathologist or automated system actually counts some of the positive-IHC-stained cells, or at least makes a visual approximation of the percentage of stained cells, and reports the results using some sort of numeric representation of the findings.

Qualitative codes: You might see some of the same antibodies you see in 88360/88361 used for qualitative IHC tests that report results as a simple positive or negative, or possibly a numeric score based on visual determination of stain intensity with no quantification. For those tests, you should not report 88360 or 88361, but instead use a different set of codes. See “88342, +88343 Clarify Immuno-Stain Coding” in Pathology/Lab Coding Alert Vol. 14 No. 12 and “G0461, G0462 Capture Qualitative IHC” in Pathology/Lab Coding Alert Vol. 15 No. 3 for a complete discussion of these codes.

Note that in the NCCI Policy Manual, CMS states that “Immunohistochemistry reported with qualitative grading such as 1+ to 4+ should be reported as HCPCS codes G0461 and G0462.” However, scoring systems such as 1+ to 4+ typically involve counting cells rather than just “qualitative grading”, which means that you should report the tests with 88360 or 88361. Check with your compliance officer and ensure that your documentation shows quantitation and you should be able to ignore this controversial CMS statement. 

Tip 3: Distinguish Manual and Automated

Because 88360-88361 state, “quantitative or semiquantitative,” coders sometimes think that’s the distinguishing feature between the two codes — false.

“The key distinction between 88360 and 88361 is whether the enumeration and evaluation is manual or computer-assisted,” Slagle says 

In other words, the way to determine the appropriate code is to know whether the counting (and perhaps other visual evaluation) is done by a human or by a microprocessor. 

For a human evaluator, whether using a microscope or a digital image on a computer to quantify and evaluate stained cells, report 88360. For an “automated” or “computer” microprocessor-determined quantification and evaluation, report 88361. 

Tip 4: Check Out the Unit of Service

You know that you should report 88360-88361 per antibody — that’s in the code definition. But don’t erroneously think that’s the only thing you need to know to report the correct number of units for these codes.

Yes, you should report a single unit of 88360 or 88361 for each distinct antibody — each distinct antibody on a single unique specimen, that is.

Opportunity: In other words, you might report multiple units of these codes for a single antibody stain enumerated for multiple specimens, or for multiple different antibody stains enumerated on a single specimen. 

Example: Using ChromaVision Automated Cellular Imaging System, the pathologist evaluates ER/PR and Her-2/neu on two blocks from a breast excision. You should report this service as 88361x3 because the evaluation involves three distinct antibodies. Although the evaluation also involves two blocks, the unit of service is “per specimen,” so you should not report 88361x6.

Tip 5: Go Global or Go Modified

If you think that choosing 88360 or 88361 is the end of the line for coding these services correctly, you’d be wrong. 

You also need to know if you’re billing the global service, or just the technical or professional components. 

Do this: Report 88360 or 88361 without a modifier for independent laboratories billing for the global service, which includes both the technical service (such as slide prep) and the professional service (pathologist interpretation).

If you’re billing for just the technical work, report either 88360 or 88361 with modifier TC (Technical component). If you’re billing only for the pathologist’s interpretation, report the appropriate code with modifier 26 (Professional component).