Q&A: Who is the primary insurer?

Q: I have a patient who has health insurance from her employer as well as Medicare because she is on dialysis. I am planning to do revision hip replacement surgery on this patient. Is Medicare her primary insurance carrier because she is on dialysis, or is it the employer-sponsored plan?

A: Your billing staff should contact Medicare to find out who is the primary carrier, though it's likely the employer-sponsored plan. This should be confirmed before the surgery is performed, since the procedure may require prior authorization. For more on determining primary carriers, read Coding Cues.