Definition
Medicare Assignment
Medicare assignment is a provider's agreement to accept the Medicare-approved amount as full payment for a covered service in Original Medicare, billing Medicare directly and charging the patient no more than the deductible and coinsurance.
1 min readReviewed September 14, 2026
Also known as: Accepting assignment, Medicare participating provider, Medicare-approved amount, Limiting charge, Medicare opt-out
Key facts
- Applies to
- Original Medicare, mainly Part B services
- Participating providers
- Sign an agreement to accept assignment on all Medicare claims
- Non-participating limit
- Limiting charge of 115% of the non-participating fee schedule amount
- Opt-out term
- 2-year periods that renew automatically unless canceled
- Mandatory assignment examples
- Services of NPs and PAs, clinical laboratory services
What is Medicare assignment?
When a doctor or supplier accepts assignment, Medicare pays its share of the approved amount directly to the provider, and the patient owes only the Part B deductible and coinsurance, usually 20% of the approved amount. Providers must submit Medicare claims for their patients whether or not they accept assignment.
Assignment governs Original Medicare billing. Medicare Advantage plans set their own network and payment terms.
How the three billing statuses work
A clinician who treats Medicare patients falls into one of three groups:
Participation decisions are generally made during an annual enrollment period and apply for the following calendar year. Some practitioners and services, including nurse practitioners, physician assistants and clinical laboratory services, must always be billed on assignment.
- Participating: the provider signs a participation agreement, accepts assignment on every Medicare claim and is paid the full fee schedule amount.
- Non-participating: the provider is enrolled but decides claim by claim whether to accept assignment. Payment uses a fee schedule 5% lower, and on unassigned claims the provider can charge the patient up to the limiting charge, 115% of that lower amount.
- Opted out: the provider files an opt-out affidavit and signs private contracts with Medicare patients, who pay the provider directly and receive no Medicare reimbursement.
Why Medicare assignment matters
Assignment status shows whether seniors can see a clinician without extra charges and how closely a practice depends on Medicare. Patients use it to find doctors who accept Medicare, and access analysts use opt-out records to spot specialties where beneficiaries face higher costs, with psychiatry a frequently cited example.
CMS publishes opt-out affidavit data, and its Doctors and Clinicians data indicates whether clinicians accept Medicare assignment. Both can be joined to other provider data by NPI.