42 C.F.R. § 411.51 : Public Health — CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES — MEDICARE PROGRAM — EXCLUSIONS FROM MEDICARE AND LIMITATIONS ON MEDICARE PAYMENT — LIMITATIONS ON MEDICARE PAYMENT FOR SERVICES COVERED UNDER LIABILITY OR NO-FAULT INSURANCE — Beneficiary's responsibility with respect to no-fault insurance

(a) The beneficiary is responsible for taking whatever action is necessary to obtain any payment that can reasonably be expected under no-fault insurance.
(b) Except as specified in §411.53, Medicare does not pay until the beneficiary has exhausted his or her remedies under no-fault insurance.
(c) Except as specified in §411.53, Medicare does not pay for services that would have been covered by the no-fault insurance if the beneficiary had filed a proper claim.
(d) However, if a claim is denied for reasons other than not being a proper claim, Medicare pays for the services if they are covered under Medicare.

42 C.F.R. §411.51