42 CFR §424.103

1. (a)General requirements.
   1. (1)The services are of the type that Medicare would pay for if they were furnished by a participating hospital.
   2. (2)The hospital has in effect an election to claim payment for all emergency services furnished in a calendar year in accordance with § 424.104.
   3. (3)The need for emergency services arose while the beneficiary was not an inpatient in a hospital.
   4. (4)In the case of inpatient hospital services, the services are furnished during a period in which the beneficiary could not be safely discharged or transferred to a participating hospital or other institution.
   5. (5)The determination that the hospital was the most accessible hospital available and equipped to furnish the services is made in accordance with § 424.106.
2. (b)Medical information requirements. A physician (or, if appropriate, the hospital) submits medical information that—
   1. (1)Describes the nature of the emergency and specifies why it required that the beneficiary be treated in the most accessible hospital;
   2. (2)Establishes that all the conditions in paragraph (a) of this section are met; and
   3. (3)Indicates when the emergency ended, which, for inpatient hospital services, is the earliest date on which the beneficiary could be safely discharged or transferred to a participating hospital or other institution.