Medicare Assignment and Part B Excess Charges: What You Could Owe

Under Original Medicare, “accepting assignment” means a doctor, other health care provider, or supplier agrees to accept the Medicare-approved amount as full payment for a covered service or item. Medicare pays its share of that approved amount, and you are responsible for your share, such as an applicable deductible or coinsurance.

Assignment does not mean the service is free, and it does not make a service covered when Medicare’s coverage rules are not met. It limits the provider’s payment for a covered service to the Medicare-approved amount and affects how the claim and your payment are handled.

Medicare.gov says most doctors, providers, and suppliers accept assignment. A participating Medicare provider has agreed to accept assignment for Medicare-covered services. The provider must submit the claim to Medicare and generally cannot ask you to pay more than the deductible and coinsurance for the approved amount.

A non-participating provider can accept the Medicare-approved amount on a case-by-case basis. If the provider does not accept assignment for your service, you may have to pay the full charge at the time of service and wait for Medicare to process the claim. Ask about the provider’s status and the specific service before the appointment.

When a non-participating provider does not accept assignment, the provider may be allowed to charge more than the Medicare-approved amount for certain Part B services. The difference above the approved amount is commonly called a Part B excess charge.

In many cases, Medicare’s limiting charge caps the provider’s charge at no more than 15% above the Medicare-approved amount. That does not mean every non-participating provider will charge the maximum, and it is not a 15% addition to your entire medical bill. The calculation depends on the covered service and the applicable Medicare payment rules.

Medicare.gov cautions that the limiting charge applies only to certain Medicare-covered services. It does not apply to some supplies and durable medical equipment, so costs can be higher in situations where the protection does not apply.

The limiting charge also does not turn a noncovered service into a covered one. Before agreeing to a service or item, ask whether Medicare is expected to cover it, whether the provider or supplier accepts assignment, what the Medicare-approved amount is, and what you may have to pay.

Some doctors and other practitioners formally opt out of Medicare. An opted-out practitioner generally uses a private contract with a Medicare patient for services that would otherwise be covered. Medicare does not pay for services covered by that private contract, and Medicare’s payment limits generally do not set the agreed price.

Read a private contract carefully before signing it. Ask what the practitioner will charge, whether another Medicare-participating provider is available, and whether the service is urgent. Different rules can apply in an emergency or urgent-care situation, so contact Medicare for help with the facts of your case.

Some standardized Medicare Supplement Insurance, or Medigap, policies include coverage for Part B excess charges. Other Medigap policies do not. Eligibility for particular policy types can depend on when you first became eligible for Medicare, and Massachusetts, Minnesota, and Wisconsin standardize Medigap differently.

Check your current policy’s official benefits rather than assuming the word “supplement” means every extra charge is covered. Medigap does not make a noncovered service payable by Medicare, and it generally does not pay claims arising from a private contract with a practitioner who opted out.

Assignment and Part B excess charges are primarily Original Medicare concepts. Medicare Advantage plans use plan-specific provider networks, contracts, referrals, prior authorization, and cost sharing. An out-of-network provider may be covered differently or not covered, depending on the plan type and circumstances.

If you have Medicare Advantage, ask both the provider and your plan whether the provider is in network for your exact plan and location. Then confirm authorization requirements and your expected copay or coinsurance. A provider saying “we take Medicare” is not the same as confirming participation in your Medicare Advantage plan.

Ask the office: Do you accept Medicare assignment for this service? Are you participating, non-participating, or opted out? Will you submit the claim? What is the estimated Medicare-approved amount, and could you bill an excess charge? Are any planned items or services not covered by Medicare?

You can search Medicare Care Compare for clinicians who accept Medicare, but confirm directly with the office because participation details can change and directory information may not answer every billing question. If you have Medigap, verify excess-charge coverage with the insurer. If you have Medicare Advantage, use the plan’s current provider directory and call the plan when network status is unclear.

Medicare.gov: “Does your provider accept Medicare as full payment?”, “What does Medicare cost?”, “Learn what Medigap Covers,” and Medicare Care Compare. These official resources explain assignment, participating and non-participating providers, the limiting charge, opted-out practitioners and private contracts, Original Medicare cost sharing, Medigap benefit differences, and how to look up providers.