Part B Insider (Multispecialty) Coding Alert

Question: Our laboratory billed the global charge for 84165, but then the pathologist, who is not employed by us, billed 84165-26. I'm concerned that the insurance company won't pay us both. What's the correct way to bill this service if our lab performs the test but a separate pathologist interprets it -- should we use modifier TC?

Answer: No, you should not use modifier TC (Technical component). The insurer should pay for the test the way it was billed:

• Your lab bills 84165 (Protein; electrophoretic fractionation and quantitation, serum)
• The pathologist bills 84165-26 (... professional component).

Here's why: Medicare splits payment for lab and pathology services into two fee schedule: the Physician fee schedule (PFS) for professional services, and the Clinical Laboratory Fee Schedule (CLFS) for technical clinical lab services.

Most codes paid on the PFS are "global" codes that represent both a technical and professional component. If you perform only the technical component, you bill the code with modifier TC, and if you perform only the professional interpretation, you bill the code with modifier 26. If you bill the code without a modifier, you're billing for both the technical and professional components.

Most codes paid on the CLFS are technical-only codes and don't require a professional interpretation. Medicare has determined that handful of these tests, such as 84165, might require professional interpretation. CMS has put a different payment mechanism in place for the technical and professional services for those codes.

Do this: The lab that performs the technical part of the test bills the code without a modifier. In your case, Medicare will pay for 84165 based on the CLFS payment amount. However, Medicare also lists 84165-26 on the PFS with a payment amount that represents only the professional interpretation for the test.