Pathology/Lab Coding Alert

Question: We're using 86356 to bill for CD45RA and CD45RO counts -- should we bill this as one antigen or two?

Texas Subscriber

Answer: You should bill two units of 86356 (Mononuclear cell antigen,quantitative [e.g., flow cytometry], not otherwise specified, each antigen) for CD45RA and CD45RO total counts.

Here's why: CD45RA and CD45RO represent two distinct antigens. CD45RA is located on Naive helper T-cells and CD45RO is located on Memory helper T-cells. If the lab quantifies each antigen separately to provide diagnostic information, you should code each individually. The code definition states that the unit of service is "each antigen."

Caveat: CPT provides many specific codes for total cell counts in the immunology section, such as 86355 (B cells, total count), 86357 (Natural killer [NK] cells, total count), and 86359 (T cells; total count). If you're testing for CD45RA and CD45RO in that context of an immunology study, you are correct to use the not-otherwise-specified (NOS) antigen code (86356) for the cell count.

If you're assessing CD45RA and CD45RO as part of a flow cytometry panel for blood or lymphoid cancers, however, you should report the entire panel using flow cytometry codes 88184-88189 (Flow cytometry ...).

Technical work: For running the panel, you would report 88184 (Flow cytometry, cell surface, cytoplasmic, or nuclear marker, technical component only; first marker) and multiple units of +88185 (... each additional marker [list separately in addition to code for first marker]) depending on the number of markers in the panel. CD45RA and CD45RO would count as two markers.

Interpretation: For the pathologist's interpretation of the panel results, you would choose one interpretation code based on the number of markers in the panel. The code choices are 88187 (Flow cytometry, interpretation; 2 to 8 markers), 88188 (... 9-15 markers), or 88189 (... 16 or more markers).