Pathology/Lab Coding Alert

You can't count on 'per marker' coding for flow cytometry anymore After eliminating 88180 and replacing it with five new codes (88184-88189), CPT 2005 sends mixed messages about flow cytometry unit of service. But you can get your flow cytometry coding right - every time - if you'll take the following steps to report the technical service and the professional interpretation: 1. Forget Everything You Knew About 88180 Before CPT 2005 eliminated the code, you used 88180 (Flow cytometry; each cell surface, cytoplasmic or nuclear marker) to report everything from clinical-lab immunology tests to the technical and professional components of lymphoma/leukemia immunophenotyping studies. For any of these tests, you reported 88180 per marker, based on the code definition. But all that's changed.

New way: Now you have five new codes - some technical, some professional - to report flow-cytometry immunophenotyping of hematolymphoid cancers:

 ICD9 88184 - Flow cytometry, cell surface, cytoplasmic, or nuclear marker, technical component only; first marker
 +88185 - ... each additional marker (list separately in addition to code for first marker)
 88187 - Flow cytometry, interpretation; 2 to 8 markers
 88188 - ... 9 to 15 markers
 88189 - ... 16 or more markers. 2. Count Markers Before You Assign Codes Counting markers sounds easy enough, but there are some pitfalls, says LuAnn Lubell, MT (ASCP), systems analyst with Ohio Health in Columbus. When you see a flow cytometry panel that lists different antibodies, such as CD5, CD10 and CD19, the count is straightforward - three markers.

But sometimes the lab uses the same antibody in various multi-color tubes that comprise a panel, and may also use the antibody for "gating," which involves finding a specific population of cells by looking at the repeat antibody in combination with other antibodies. "Gating and multi-color tubes have led to some questions about how to count the markers," Lubell says.

Labs commonly evaluate the same antibody in multiple combinations. "We often run a tube with CD5/CD19, as well as evaluating CD5 alone and CD19 alone," says Walt Williams, billing and reimbursement specialist with Genoptix in San Diego. Although that's two antibodies in the first tube and one antibody in each subsequent test, for a total of four antibodies, "we bill the test as two markers," Williams says.

How to do it: For flow cytometry coding, don't count repeat antibodies. "Until we introduce a unique antibody into the assay, we don't code it separately," Williams says. When you code a flow cytometry report, you should count each unique CD# (or other marker name) that you see, and never count the same marker name more than once.

Although a lot of technical work goes into gating multiple antibodies, the thinking behind the CPT technical codes [...]