Which term refers to a physician who is not part of the Medicare program yet provides services to beneficiaries?

The term that accurately describes a physician who does not participate in the Medicare program while still providing services to Medicare beneficiaries is indeed "non-participating physician." Non-participating physicians are not enrolled in the Medicare program and choose not to accept Medicare assignment for all of their services. When they provide care to Medicare beneficiaries, they can still bill for services but do so at a higher fee than the Medicare-approved amount. Furthermore, non-participating physicians may decide whether to accept Medicare assignments on a case-by-case basis for individual services.

In contrast, participating physicians agree to accept Medicare assignment, meaning they accept the Medicare-approved amount as full payment for their services. Network physicians are typically part of insurance networks that negotiate prices with insurance companies, while out-of-network physicians do not have agreements with specific insurance plans and often charge higher fees without those plans' negotiated rates. Thus, the definition of a non-participating physician specifically aligns with the inquiry about those who do not take part in the Medicare program while providing care to its beneficiaries.