Pathology/Lab Coding Alert

Counting cells earns semiquantitative pay

Don't be confused by reports that IHC grading systems such as 1+, 2+, 3+, 4+ are qualitative. As long as the pathologist counts cells as part of the morphometric analysis, you should be able to use IHC codes 88360- 88361 for the service - even if the pathologist reports the results on a semiquantitative grading scale.

Caution: Both Medicare and the College of American Pathologists (CAP) have published directions indicating that you should bill qualitative IHC tests scored with a range such as 1+ to 4+ as 88342 Codes (Immunohistochemistry [including tissue immunoperoxidase], each antibody) (see editor's note below).

But you should be able to challenge your payers to allow CPT 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) for semiquantitative grading (0 to 3+), says Joan Logue, BS, MT-ASCP, principal with Health Systems Concepts Inc. in Longwood, Fla.

Grading Scale - Counting or Intensity?

Common IHC tumor morphometry tests such as Her-2/neu that use a reporting scale of 0 to 3+ involve counting cells as a component of the grading. "If the scoring requires the pathologist to count cells to evaluate percentage of cell staining, 88360 or 88361 describes the procedure better than 88342," says Christian Hansen, MD, pathologist with Northwest Hospital Center in Randallstown, Md.

Some grading scales, especially of older IHC tests, may involve only a qualitative evaluation of staining intensity (such as 1+ to 4+), and may warrant 88342, Hansen says.

Example: The lab prepares Her-2/neu breast tumor slides using DakoCytomation HercepTest. The pathologist counts cells to determine whether membrane staining is present in greater or less than 10 percent of tumor cells. Coupling the count with observations about the stain intensity, the pathologist scores the test as 0 (membrane staining in less than 10 percent of tumor cells), 1+ (faint membrane staining in greater than 10 percent of tumor cells), 2+ (moderate membrane staining in greater than 10 percent of tumor cells), or 3+ (strong, complete membrane staining in greater than 10 percent of tumor cells).

This grading system requires the pathologist to count cells to determine if staining occurs in greater or less than 10 percent of tumor cells. "You can make a strong case to payers that this is a semiquantitative test, and the appropriate code for the service is 88360 [or 88361 if computer-assisted]," Logue says.

Editor's note: In the National Correct Coding Policy Manual, version 10.3, available on the Internet at www.cms.hhs.gov/physicians/cciedits/chap10.pdf, Medicare states, "Immunohistochemistry reported with qualitative grading such as 1+ to 4+ should be reported as 88342." Similarly, in the December 2004 issue of CAP Today, available on the Internet at www.cap.org/apps/docs/cap_today/feature_stories/1204cptchanges.html, CAP states, "Immunohistochemistry reported with qualitative grading, such as 1+ to 3+, should be reported as 88342."