42 CFR § 411.7
Services that must be furnished at public expense under a Federal law or Federal Government contract
June 11, 2020
(a) Basic rule. Except as provided in paragraph (b) of this section, payment may not be made for services that any provider or supplier is obligated to furnish at public expense, in accordance with a law of, or a contract with, the United States.
(b) Exception. Payment may be made for services that a hospital or SNF of the Indian Health Service is obligated to furnish at public expense.