Pathology/Lab Coding Alert

Question: We have a patient on Medicare who is also insured through a group health plan from a small business. We know the Medicare Secondary Payer rules, but how do we determine when Medicare is the primary insurance?

Nevada Subscriber

Answer: Although most practices understand Medicare Secondary Payer rules, you’re not alone in your confusion about how to know when Medicare is the primary payer. 

There are myriad patient circumstances that determine which insurer should be billed first and when that payer is Medicare. Here’s a list of when Medicare is the primary payer:

• Patient is age 65 or older and covered by both Medicare and a group health plan for an employer with less than 20 employees.
• Patient is 65 or older and has a retirement group health plan through her employer but is no longer working.
• Patient is under the age of 65 but entitled to Medicare, is disabled, is covered by a group health plan through an employer or a family member’s employer, and the employer has fewer than 100 employees.
• Patient has end-stage renal disease and group health plan coverage, and 30 months of Medicare eligibility or entitlement have already passed.
• Patient has end-stage renal disease and COBRA coverage, and 30 months of Medicare eligibility or entitlement have already passed.
• Patient is age 65 or older OR disabled and is covered by both COBRA and Medicare.
• Patient is dually eligible for both Medicare and Medicaid.
• Patient is covered by Medicare and also has a Medigap or supplemental insurance plan.
• Patient has both Tricare and Medicare but is on inactive military status and is being treated by civilian providers.