42 C.F.R. § 136.506 – Alternate resources.

(a) Expenses paid by alternate resources are not eligible for payment by PRC or reimbursement by the CHEF. No payment shall be made from the CHEF to any Service Unit to the extent that the provider of services is eligible to receive payment for the treatment from any other Federal, State, local, or private source of reimbursement for which the patient is eligible. A patient shall be considered eligible for such resources and no payment shall be made from the CHEF if:
1. (1) The patient is eligible for alternate resources; or
2. (2) The patient would be eligible for alternate resources if he or she were to apply for them; or
3. (3) The patient would be eligible for alternate resources under Federal, State, or local law or regulation but for the patient's eligibility for PRC, or other health services, from the Indian Health Service or Indian Health Service funded programs.
(b) Patients are not required to expend personal resources for health services to meet alternate resource eligibility, nor are they required to sell valuables or property to become eligible for alternate resources.
(c) When a PRC program pays primary to (i.e., before) a Tribal self-insurance plan, this will not impact whether the PRC program's expenditures are eligible for reimbursement from the CHEF, as long as the Service Unit clearly demonstrates that the PRC program was responsible and did in fact assume that responsibility by making the payments at issue in the CHEF request.
(d) The determination of whether a resource constitutes an alternate resource for the purpose of the CHEF reimbursement shall be made by the Headquarters of the Indian Health Service, irrespective of whether the resource was determined to be an alternate resource at the time of PRC payment.