For the patient with both a Medicare and a secondary insurance through employment, which exists as the primary payer?

In the scenario where a patient has both Medicare and a secondary insurance through employment, the secondary insurance is generally considered the primary payer for certain services. In this case, Medicare Part B is the correct primary payer, especially when the employment-based insurance is a supplementary plan rather than a primary insurance plan. This is especially true for non-hospital services, as Medicare Part B covers outpatient care, doctor visits, and preventive services.

When someone is actively employed and has coverage through their employer, that coverage can serve as the primary payer for medical services. However, if the employer's plan is small (typically with 20 or fewer employees), Medicare generally becomes the primary payer, leaving the employer-sponsored insurance to cover costs not fully addressed by Medicare.

This specific knowledge about the order of benefits coordination for Medicare and employer insurance is crucial for efficient patient access and service. Therefore, Medicare Part B being recognized as the primary payer in this situation aligns with established guidelines on financial responsibilities among payers.