If a provider does not accept assignment of Medicare insurance, they are referred to as what?

The term used for providers who do not accept assignment of Medicare insurance is "nonparticipating providers." These providers have the option to accept or decline Medicare assignment on a case-by-case basis. When they choose not to accept assignment, they can charge patients more than the Medicare-approved amount, and the patient is responsible for paying the difference, in addition to potential deductibles and coinsurance.

Participating providers, on the other hand, agree to accept Medicare’s approved amounts for services, which means they cannot charge patients more than that amount. Accepting providers is not a standard term used in this context, and excluded providers typically refer to those who are barred from participating in Medicare due to various issues, such as misconduct or failure to meet standards.