Medicare Assignment: Everything You Need to Know

Medicare assignment is an agreement between Medicare and medical providers (doctors, hospitals, medical equipment suppliers, etc.) in which the provider agrees to accept Medicare’s fee schedule as payment in full when Medicare patients are treated.

This article will explain how Medicare assignment works, and what you need to know in order to ensure that you won’t receive unexpected bills.

Woman checks paperwork for Medicare benefits

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Medicare Assignment

There are 35 million Americans who have Original Medicare. Medicare is a federal program and most medical providers throughout the country accept assignment with Medicare. As a result, these enrollees have a lot more options for medical providers than most of the rest of the population.

They can see any provider who accepts assignment, anywhere in the country. They can be assured that they will only have to pay their expected Medicare cost-sharing (deductible and coinsurance, some or all of which may be paid by a Medigap plan, Medicaid, or supplemental coverage provided by an employer or former employer).

It’s important to note here that the rules are different for the 29 million Americans who have Medicare Advantage plans. These beneficiaries cannot simply use any medical provider who accepts Medicare assignment.

Instead, each Medicare Advantage plan has its own network of providers—much like the health insurance plans that many Americans are accustomed to obtaining from employers or purchasing in the exchange/marketplace.

A provider who accepts assignment with Medicare may or may not be in-network with some or all of the Medicare Advantage plans that offer coverage in a given area. Some Medicare Advantage plans—health maintenance organizations (HMOs), in particular—will only cover an enrollee’s claims if they use providers who are in the plan's network.

Other Medicare Advantage plans—preferred provider organizations (PPOs), in particular—will cover out-of-network care but the enrollee will pay more than they would have paid had they seen an in-network provider.

Original Medicare

The bottom line is that Medicare assignment only determines provider accessibility and costs for people who have Original Medicare. People with Medicare Advantage need to understand their own plan’s provider network and coverage rules.

When discussing Medicare assignment and access to providers in this article, keep in mind that it is referring to people who have Original Medicare.

How to Make Sure Your Provider Accepts Assignment

Most doctors, hospitals, and other medical providers in the United States do accept Medicare assignment.

Provider Participation Stats

According to the Centers for Medicare and Medicaid Services, 98% of providers participate in Medicare, which means they accept assignment.

You can ask the provider directly about their participation with Medicare. But Medicare also has a tool that you can use to find participating doctors, hospitals, home health care services, and other providers.

There’s a filter on that tool labeled “Medicare-approved payment.” If you turn on that filter, you will only see providers who accept Medicare assignment. Under each provider’s information, it will say “Charges the Medicare-approved amount (so you pay less out-of-pocket).”

What If Your Provider Doesn’t Accept Assignment?

If your medical provider or equipment supplier doesn’t accept assignment, it means they haven’t agreed to accept Medicare’s approved amounts as payment in full for all of the services.

These providers can still choose to accept assignment on a case-by-case basis. But because they haven’t agreed to accept Medicare assignment for all services, they are considered nonparticipating providers.

Note that "nonparticipating" does not mean that a provider has opted out of Medicare altogether. Medicare will still pay claims for services received from a nonparticipating provider (i.e., one who does not accept Medicare assignment), whereas Medicare does not cover any of the cost of services obtained from a provider who has officially opted out of Medicare.

If a Medicare beneficiary uses a provider who has opted out of Medicare, that person will pay the provider directly and Medicare will not be involved in any way.

Physicians Who Have Opted Out

Only about 1% of all non-pediatric physicians have opted out of Medicare.

For providers who have not opted out of Medicare but who also don’t accept assignment, Medicare will still pay nearly as much as it would have paid if you had used a provider who accepts assignment. Here’s how it works:

  • Medicare will pay the provider 95% of the amount they would pay if the provider accepted assignment.
  • The provider can charge the person receiving care more than the Medicare-approved amount, but only up to 15% more (some states limit this further). This extra amount, which the patient has to pay out-of-pocket, is known as the limiting charge. But the 15% cap does not apply to medical equipment suppliers; if they do not accept assignment with Medicare, there is no limit on how much they can charge the person receiving care. This is why it’s particularly important to make sure that the supplier accepts Medicare assignment if you need medical equipment.
  • The nonparticipating provider may require the person receiving care to pay the entire bill up front and seek reimbursement from Medicare (using Form CMS 1490-S). Alternatively, they may submit a claim to Medicare on behalf of the person receiving care (using Form CMS-1500).
  • A nonparticipating provider can choose to accept assignment on a case-by-case basis. They can indicate this on Form CMS-1500 in box 27. The vast majority of nonparticipating providers who bill Medicare choose to accept assignment for the claim being billed.
  • Nonparticipating providers do not have to bill your Medigap plan on your behalf.

Billing Options for Providers Who Accept Medicare

When a medical provider accepts assignment with Medicare, part of the agreement is that they will submit bills to Medicare on behalf of the person receiving care. So if you only see providers who accept assignment, you will never need to submit your own bills to Medicare for reimbursement.

If you have a Medigap plan that supplements your Original Medicare coverage, you should present the Medigap coverage information to the provider at the time of service. Medicare will forward the claim information to your Medigap insurer, reducing administrative work on your part.

Depending on the Medigap plan you have, the services that you receive, and the amount you’ve already spent in out-of-pocket costs, the Medigap plan may pay some or all of the out-of-pocket costs that you would otherwise have after Medicare pays its share.

(Note that if you have a type of Medigap plan called Medicare SELECT, you will have to stay within the plan’s network of providers in order to receive benefits. But this is not the case with other Medigap plans.)

After the claim is processed, you’ll be able to see details in your MyMedicare.gov account. Medicare will also send you a Medicare Summary Notice. This is Medicare’s version of an explanation of benefits (EOB), which is sent out every three months.

If you have a Medigap plan, it should also send you an EOB or something similar, explaining the claim and whether the policy paid any part of it.

What Is Medicare Assignment of Benefits?

For Medicare beneficiaries, assignment of benefits means that the person receiving care agrees to allow a nonparticipating provider to bill Medicare directly (as opposed to having the person receiving care pay the bill up front and seek reimbursement from Medicare). Assignment of benefits is authorized by the person receiving care in Box 13 of Form CMS-1500.

If the person receiving care refuses to assign benefits, Medicare can only reimburse the person receiving care instead of paying the nonparticipating provider directly.

Things to Consider Before Choosing a Provider

If you’re enrolled in Original Medicare, you have a wide range of options in terms of the providers you can use—far more than most other Americans. In most cases, your preferred doctor and other medical providers will accept assignment with Medicare, keeping your out-of-pocket costs lower than they would otherwise be, and reducing administrative hassle.

There may be circumstances, however, when the best option is a nonparticipating provider or even a provider who has opted out of Medicare altogether. If you choose one of these options, be sure you discuss the details with the provider before proceeding with the treatment.

You’ll want to understand how much is going to be billed and whether the provider will bill Medicare on your behalf if you agree to assign benefits (note that this is not possible if the provider has opted out of Medicare).

If you have supplemental coverage, you’ll also want to check with that plan to see whether it will still pick up some of the cost and, if so, how much you should expect to pay out of your own pocket.

Summary

A medical provider who accepts Medicare assignment is considered a participating provider. These providers have agreed to accept Medicare’s fee schedule as payment in full for services they provide to Medicare beneficiaries. Most doctors, hospitals, and other medical providers do accept Medicare assignment.

Nonparticipating providers are those who have not signed an agreement with Medicare to accept Medicare’s rates as payment in full. However, they can agree to accept assignment on a case-by-case basis, as long as they haven’t opted out of Medicare altogether. If they do not accept assignment, they can bill the patient up to 15% more than the Medicare-approved rate.

Providers who opt out of Medicare cannot bill Medicare and Medicare will not pay them or reimburse beneficiaries for their services. But there is no limit on how much they can bill for their services.

A Word From Verywell

It’s in your best interest to choose a provider who accepts Medicare assignment. This will keep your costs as low as possible, streamline the billing and claims process, and ensure that your Medigap plan picks up its share of the costs.

If you feel like you need help navigating the provider options or seeking care from a provider who doesn’t accept assignment, the Medicare State Health Insurance Assistance Program (SHIP) in your state may be able to help.

Frequently Asked Questions

  • What does it mean when a doctor does not accept Medicare assignment?

    A doctor who does not accept Medicare assignment has not agreed to accept Medicare’s fee schedule as payment in full for their services. These doctors are considered nonparticipating with Medicare and can bill Medicare beneficiaries up to 15% more than the Medicare-approved amount.

    They also have the option to accept assignment (i.e., accept Medicare’s rate as payment in full) on a case-by-case basis.

  • What is mandatory assignment Medicare?

    There are certain circumstances in which a provider is required by law to accept assignment. This includes situations in which the person receiving care has both Medicare and Medicaid. And it also applies to certain medical services, including lab tests, ambulance services, and drugs that are covered under Medicare Part B (as opposed to Part D).

  • What percentage of doctors do not accept Medicare assignment?

    In 2021, 98% of American physicians had participation agreements with Medicare, leaving only about 2% who did not accept assignment (either as a nonparticipating provider, or a provider who had opted out of Medicare altogether).

  • What is the difference between accepting assignment and assignment of benefits?

    Accepting assignment is something that the medical provider does, whereas assignment of benefits is something that the patient (the Medicare beneficiary) does. To accept assignment means that the medical provider has agreed to accept Medicare’s approved fee as payment in full for services they provide.

    Assignment of benefits means that the person receiving care agrees to allow a medical provider to bill Medicare directly, as opposed to having the person receiving care pay the provider and then seek reimbursement from Medicare.

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10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Medicare and Medicaid Services. Annual Medicare participation announcement.

  3. Centers for Medicare and Medicaid Services. Lower costs with assignment.

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  9. Centers for Medicare and Medicaid Services. Ambulance fee schedule.

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