Medicare coordination of benefits determines which insurance pays first when you have multiple health plans. This system prevents overpayment and ensures correct coverage.
When you have Medicare plus another insurance plan, coordination of benefits establishes which plan pays first (primary payer) and which pays second (secondary payer). Medicare always follows the same rules for determining primary and secondary payers.
Primary payers process claims first. Secondary payers review the primary payer's payment and cover the remaining costs up to their policy limits. For example, if your primary insurer pays $6,000 toward a $10,000 bill, your secondary insurer covers the remaining $4,000.
| Plan Type | Primary Payer | Secondary Payer |
|---|---|---|
| Employer or union group health plan | Employer/union plan | Medicare |
| COBRA coverage | COBRA plan | Medicare |
| Retiree health benefits | Retiree plan | Medicare |
| Medicare and Medicaid | Medicare | Medicaid |
Many people assume Medicare always pays first. However, employer-based plans typically take precedence over Medicare for those under 65. Another misconception is that coordination only applies to retirees, but it affects anyone with multiple health plans, including workers with disabilities.
A common mistake is not informing both insurers about your other coverage. Always provide your Medicare number and any other insurance details to all providers and plans involved.
Coordination of benefits prevents financial waste by avoiding duplicate payments. According to the Centers for Medicare & Medicaid Services, proper coordination saves billions annually by ensuring each payer covers only their share of medical expenses.
Without coordination, you might receive bills for services your secondary insurer should have covered. Proper coordination also ensures you receive all benefits you're entitled to from each plan.
When my father retired and gained Medicare eligibility while still covered by his employer plan, we had to coordinate benefits carefully. His employer plan remained primary, and Medicare became secondary. We notified both insurers and provided all necessary documentation to avoid claim denials and ensure proper coverage.
One challenge was understanding which plan covered specific services. For example, his employer plan covered most prescription drugs, while Medicare Part D filled gaps. Keeping detailed records helped us track payments and identify any discrepancies.