Many Americans over 65 have more than one type of health insurance. You may still have employer or spouse coverage, Original Medicare, or even retiree or Medicaid plans.

But how do you know which plan pays first, or which coverage to use in each situation?

Understanding how your Medicare plan coordinates with other insurance is essential to avoid unexpected bills, claim denials, and lost benefits.

This guide explains, in clear and practical terms, how benefits coordination works with Medicare.

1. What Is “Benefits Coordination”?

Benefits coordination (COB) determines which plan pays first (primary plan) and which pays after (secondary plan).
This is important when a person has more than one source of coverage.

For example:

• If you are still working and have employer coverage, that plan may pay first.

• Medicare would then cover remaining costs, depending on the service and plan.

Knowing the correct order helps prevent duplicate payments or claim issues.

2. What Plans Can Coordinate With Medicare?

Several types of insurance can coexist with Medicare. Here’s a breakdown:

a. Employer Insurance (Active or Spouse Coverage)

If you continue working past 65, or your spouse does, you may keep group coverage.

• Employers with 20 or more employees: Employer plan pays first, Medicare pays second.

• Employers with fewer than 20 employees: Medicare pays first.

👉 Tip: Always notify your employer when you enroll in Medicare to avoid payment issues.

b. COBRA

COBRA allows you to temporarily keep your employer’s insurance after leaving a job.

• If you are enrolled in Medicare, Medicare pays first.

• COBRA covers what Medicare does not.

Waiting to enroll in Medicare after COBRA ends may result in late enrollment penalties.

c. Retiree Coverage

Some companies or unions offer retiree health benefits.

• Medicare pays first, and the retiree plan covers remaining costs.

d. Medicaid

If you qualify for both Medicare and Medicaid (dual eligible):

• Medicare pays first for approved services.

• Medicaid pays second, covering copays and deductibles based on income.

This ensures you are protected from high out-of-pocket expenses.

e. TRICARE and VA (Veterans Affairs)

If you are a veteran, you may have coverage through VA or TRICARE.

• Medicare and VA do not coordinate directly; services must be received at VA facilities.

• TRICARE for Life complements Medicare: Medicare pays first, TRICARE pays remaining costs.

3. How Coordination Works With Medicare Advantage (Part C)

If you have a Medicare Advantage (Part C) plan, it replaces Original Medicare (Parts A and B).
Payments and coverage are handled directly by your private plan.

• If you also have employer insurance, it may cover services that the Advantage plan does not.

• Do not enroll in Medicare Advantage and keep a Medigap plan at the same time.

Important: Medigap plans do not work with Medicare Advantage.

4. Supplemental Plans (Medigap): How They Work

A Medigap plan is private insurance designed to cover costs that Original Medicare doesn’t cover, such as deductibles, copays, and coinsurance.

• Medicare pays first, and Medigap pays second.

• Medigap does not work with Medicare Advantage.

These plans offer financial security, especially for beneficiaries who use medical services frequently.

5. What to Do If You Have Multiple Plans

If you have more than one coverage, follow these steps:

1. List all your active plans, including employer, retiree, Medicare, Medicaid, etc.

2. Check who pays first using Medicare’s benefits coordination resources or by calling 1-800-MEDICARE.

3. Inform all healthcare providers about your coverage to avoid claim denials.

4. Keep benefit summaries for reference, in case of errors or duplicate billing.

6. How to Maximize Your Combined Coverage

Having multiple plans doesn’t always mean lower costs. The key is to understand how they complement each other:

• Check deductibles and copays for each plan.

• Avoid unnecessary duplicate coverage.

• Use in-network providers to maximize benefits.

• Consult a certified Medicare advisor, such as those at SF Solutions, to compare options.

7. Common Mistakes When Coordinating Benefits

• Failing to notify Medicare of other active coverage.

• Paying for out-of-network services expecting both plans to cover.

• Enrolling in Medicare Advantage without canceling COBRA or Medigap.

• Not reviewing payment order annually, especially if employment status changes.

Avoiding these mistakes can save hundreds or even thousands of dollars each year.

Understanding how your Medicare plan coordinates with other insurance allows you to maximize your benefits and protect your finances.

Whether you are working, retired, or eligible for government coverage, knowing the payment order and coordination rules is crucial to keeping your healthcare affordable and accessible.

At SF Solutions, we help Medicare beneficiaries understand, compare, and optimize their coverage, so they can make informed decisions without stress.