How to Know Which Insurance Pays First

When you have both Medicare and Medicaid, Medicare pays first for most medical services. Medicaid then pays what Medicare does not cover, up to what your state allows. This order matters because it changes what you owe out of pocket and which rules explore to your care.

The person or organization providing the service — your doctor, hospital, or pharmacy — must bill Medicare first. After Medicare processes the claim and pays its share, the provider then bills Medicaid for the remaining balance. You should not have to manage this billing order yourself; the provider's office handles it.

There are a few exceptions where Medicaid pays first instead. These happen in specific situations: when you are in a nursing home or long-term care facility, when you receive services through a Medicaid-only program, or when the service is covered by Medicaid but not by Medicare. Your state Medicaid office can tell you whether an exception applies to your situation.

Key Takeaways

  • Medicare is the primary payer for most services when you have both programs, meaning it processes your claim and pays first.
  • Medicaid covers what Medicare leaves unpaid, including copayments, coinsurance, and deductibles that Medicare does not pay.
  • The provider's billing department is responsible for sending claims to Medicare first, then to Medicaid — you do not need to direct the order.
  • Nursing home care, certain long-term services, and Medicaid-only programs may reverse this order and have Medicaid pay first in your state.
  • Your state Medicaid program can confirm the payment order for any specific service you are unsure about.

What Medicare Covers and What It Leaves Unpaid

Medicare covers hospital stays, doctor visits, lab work, imaging, and many other services once you meet your annual deductible. However, Medicare does not cover everything. You are responsible for copayments (a flat fee per visit), coinsurance (a percentage of the cost), and any charges above what Medicare considers reasonable.

For example, if you see a doctor and Medicare allows $100 for that visit, Medicare might pay $80 and you owe $20 as coinsurance. If the doctor charges $120, you also owe the $20 difference between the allowed amount and the actual charge. These gaps — the $20 coinsurance and the $20 overage — are where Medicaid steps in.

Medicaid in your state will pay some or all of these gaps, depending on your income and which Medicaid program you are in. Some states cover the full amount; others cover only part of it. Your state Medicaid office has a list of what it covers for people with both programs.

How Medicaid Fills the Gaps Medicare Leaves

Once Medicare pays its share, Medicaid receives the claim and decides what to pay. Medicaid looks at what Medicare paid, what you owe, and what your state's rules allow. Medicaid then pays the provider directly for its portion.

The result is that you owe less out of pocket. Instead of paying the full $40 in the example above (the $20 coinsurance plus the $20 overage), Medicaid might cover part or all of it. The exact amount depends on your state and your Medicaid category.

This is why having both programs is valuable: Medicare handles the main medical costs, and Medicaid reduces what you have to pay from your own pocket. Without Medicaid, you would owe those gaps yourself.

When Medicaid Pays First Instead

In a few situations, Medicaid becomes the primary payer and Medicare pays second. The most common is when you live in a nursing home or receive long-term care services. In these cases, Medicaid often pays first because it covers the full cost of care, while Medicare covers only limited skilled nursing stays.

Some Medicaid programs that focus on long-term services and supports — such as home care, adult day programs, or assisted living — may also have Medicaid pay first. Additionally, if a service is covered only by Medicaid and not by Medicare, Medicaid pays first because Medicare has nothing to pay.

Your state Medicaid program can tell you whether any of your regular services fall into these exceptions. If you are unsure, contact your state Medicaid office or your case manager before scheduling a service.

What to Tell Your Doctor and Hospital

When you schedule an appointment or check in at a hospital, tell the front desk that you have both Medicare and Medicaid. Provide both insurance cards. The billing staff will use this information to set up the correct payment order in their system.

You do not need to explain the payment order to them — they know Medicare comes first. Your job is straightforward to make sure they have both card numbers and know you have both programs. If you only give them one card, they may not bill the other, and you could end up owing more than you should.

If you receive a bill that seems wrong — for example, if you are charged the full copayment when Medicaid should have covered it — contact the provider's billing department. Ask them to check whether they billed both Medicare and Medicaid. Often the bill is a mistake that gets corrected once they process the Medicaid claim.

How to Check Your Claim Status

After you receive care, both Medicare and Medicaid will send you documents showing what they paid. Medicare sends an Explanation of Benefits (EOB), and Medicaid sends a similar document called an Explanation of Payment (EOP) or Remittance information.

These documents show what the provider charged, what Medicare paid, what Medicaid paid, and what you owe. Keep them in case there is a billing dispute. If you do not receive these documents within two to three weeks, contact Medicare or your state Medicaid office to ask for copies.

You can also check your claims online. Medicare has a tool called Medicare.gov Claim Status where you can log in and see recent claims. Your state Medicaid program has a similar online portal; the web address varies by state, but your Medicaid card or your state's Medicaid website will have the link.

Common Mistakes and How to Avoid Them

The biggest mistake is telling a provider you have only one insurance. If you do not mention Medicaid, the provider bills only Medicare, and you end up paying the gaps yourself. Always hand over both cards and say you have both programs.

Another mistake is assuming Medicaid will cover everything Medicare does not. Medicaid has its own limits and rules. Some services Medicare covers, Medicaid does not. Some services Medicaid covers, Medicare does not. You may still owe money even with both programs.

A third mistake is ignoring bills that look wrong. If you receive a bill for an amount that seems too high, do not assume it is correct. Call the provider and ask them to verify that they billed both insurances. Many billing errors get fixed once you ask.

Frequently Asked Questions

What if a provider only accepts Medicare and not Medicaid?

Some providers do not accept Medicaid. In that case, Medicare is your only insurance for that provider, and you pay the Medicare copayments and coinsurance yourself. Medicaid cannot pay for services from a provider it does not have a contract with. Ask the provider's office whether they accept Medicaid before you schedule.

Do I have to pay anything out of pocket if I have both Medicare and Medicaid?

It depends on your state and your Medicaid category. Some people with both programs pay nothing out of pocket because Medicaid covers all the gaps Medicare leaves. Others pay small copayments that Medicaid does not cover. Your state Medicaid office can tell you what you are responsible for.

What happens if Medicare and Medicaid disagree about what to cover?

This is rare, but if it happens, the provider usually follows Medicare's decision since Medicare is primary. If you believe the decision is wrong, you can file an appeal with Medicare. Your state Medicaid office can also help you understand why a service was or was not covered.

Can I choose which insurance pays first?

No. The law sets the payment order: Medicare pays first for most services. You cannot change this order. However, you can choose which providers you use, and some providers may have different rules about how they handle dual coverage.

How do I know if I have the right Medicaid program for someone with Medicare?

Contact your state Medicaid office and tell them you have Medicare. They can confirm which Medicaid program you are in and explain what it covers. Some states have programs specifically designed for people with both Medicare and Medicaid, and you may be in one of them.