Final answer:
An Advance Beneficiary Notice is required for a Medicare patient when a procedure or test may not be covered by Medicare, to inform them about possible charges they might incur.
Step-by-step explanation:
An Advance Beneficiary Notice (ABN) is a written notice a provider or supplier gives to a Medicare beneficiary before items or services are furnished when it is believed that Medicare may not pay for some or all of the items or services. The correct answer to the scenario you provided is C: A Medicare patient has a procedure or test that may not be covered by Medicare.
A provider is required to issue an ABN when the provider believes that Medicare will not cover a certain service due to such reasons as it is not considered medically necessary or is considered experimental. This is to notify the patient that they may be responsible for the payment, and it allows them to make an informed decision about whether to receive the service and accept potential financial responsibility.