Pathology/Lab Coding Alert

You just got used to using 86586 for unlisted cell types in an immunodeficiency panel -- now you have to adjust to using 86356 instead.

Here's why: CPT 2008 deletes 86586 (Unlisted antigen, each) and adds two codes in its place:

- 86356 -- Mononuclear cell antigen, quantitative (e.g., flow cytometry), not otherwise specified, each antigen

- 86486 -- Skin test; unlisted antigen, each.

"The change is a welcome clarification for coders reporting immunodeficiency panels or skin tests," says Karen Kavanaugh, RHIT, compliance auditor with Labcorp in Oklahoma City.

Beginning with code changes in CPT 2005 and continuing with the current 86586 deletion, CPT enforces a clear delineation between flow cytometry cancer studies and immunodeficiency coding. Although both types of testing use flow cytometry methodology and may even involve some of the same cell types, CPT assigns distinctly different code sets for the two tests.

Do this: You should use only immunology codes 86355-86367 for immune-response cell-count studies that don't normally require a pathologist's interpretation -- even if the method involves flow cytometry, Kavanaugh says.

After adding some of these code definitions in 2005 and then reassigning code numbers in past years and again this year, CPT finally arranges all the immunodeficiency test codes in one consecutive grouping:

- 86355 -- B cells, total count

- 86356 -- Mononuclear cell antigen, quantitative (e.g., flow cytometry), not otherwise specified, each antigen

- 86357 -- Natural killer (NK) cells, total count

- 86359 -- T cells; total count

- 86360 -- T cells; absolute CD4 and CD8 count, including ratio

- 86361 -- T cells; absolute CD4 count

- 86367 -- Stem cells (i.e., CD34), total count.

Don't miss: A new CPT text note following 86580 states, "86586 has been deleted ... For flow cytometry, quantitative, not otherwise specified, use 86356."

Example: The lab receives an order for an immune dysfunction panel that includes CD3 (total T cells), CD4 (helper cells), CD8 (suppressor cells), CD4/CD8 ratio, CD3/HLA-DR, CD8/CD38, CD8/CD28, and CD19 (B cells). The lab reports the results, with no morphologic review by the pathologist and no interpretive report.

Solution: Report the service this way: 86359 for T cell total count (CD3); 86360 for CD4 and CD8 absolute counts and ratio; 86355 for B cell total count; and three units of 86356 -- one for each marker: HLA-DR, CD38 and CD28.

Reserve the flow cytometry codes (88184-88189) for immunophenotyping of hematolymphoid cancers. Pathologists often use these studies as an adjunct test for surgical pathology specimens. The flow cytometry testing involves panels of "markers" that require interpretation by the pathologist.

"Report 88184 (Flow cytometry, cell surface, cytoplasmic, or nuclear marker, technical component only; first marker) and +88185 (- each additional marker [list separately in addition to code for first marker]) for the technical component of the study," says Peggy Slagle, CPC, billing compliance coordinator at the University of Nebraska Medical Center in Omaha.

To report the professional interpretation based on the number of markers, use one of the following codes:

- 88187 -- Flow cytometry, interpretation; 2 to 8 markers

- 88188 -- - 9 to 15 markers

- 88189 -- - 16 or more markers.

When coding a pathologist's cancer study flow cytometry panel that includes listed cell types such as B cells, you might be tempted to use the immunology B cell code (86355) -- don't do it if you want to get paid.

Conversely, when coding a flow-cytometry immuno-deficiency panel that includes an unlisted cell type, you might be tempted to use the flow cytometery marker codes (88184-88189) -- don't do that either if you want to follow CPT coding rules. In fact, a new CPT text note following 86356 and 88189 states, "Do not report 88187-88189 for interpretation of 86355, 86356, 86357, 86359, 86360, 86361, 86367."

Hard and fast rule: Report immunodeficiency panels using codes only from the range 86355-86367. List flow cytometry cancer studies using codes only from the range 88184-88189.

Example: Suspecting lymphoma in a lymph node biopsy specimen, the pathologist runs a flow cytometry panel consisting of CD3 (total T cells), CD4, CD5, CD8, CD10, CD14, CD16/56 (NK cells), CD19 (B cells), CD20, CD23, CD45, kappa, and lambda.

Solution: The flow cytometry panel consists of 13 different antibody markers. You should report 88184 plus 12 units of 88185 for the technical component of the panel. For the pathologist's interpretation, report 88188 (Flow cytometry, interpretation; 9 to 15 markers).

Although CPT provides separate codes in the immunology section for T cells (86359), B cells (86355) and NK cells (86357), you should not use these codes for this example. Rationale: Because the procedure is an evaluation for suspected lymphoma and involves the pathologist's professional interpretation of the entire panel, you should report the complete service using the flow cytometry codes.