42 C.F.R. § 136.501
Alternate resources means health care resources other than those of the Indian Health Service (IHS or Service). Such resources include health care providers and institutions, and health care programs for the payment of health services including but not limited to programs under title XVIII or XIX of the Social Security Act (i.e., Medicare, Medicaid), State or local health care programs, and private insurance.
Catastrophic Health Emergency Fund (CHEF) means the fund established by Congress to reimburse extraordinary medical expenses incurred for catastrophic illnesses and disasters paid by a purchased/referred care (PRC) program of the IHS, whether such program is carried out by the IHS or an Indian Tribe or Tribal Organization under the Indian Self-Determination and Education Assistance Act (ISDEAA).
Catastrophic illness refers to a medical condition that is costly by virtue of the intensity and/or duration of its treatment. Examples of conditions that frequently require multiple hospital stays and extensive treatment are cancer, burns, premature births, cardiac disease, end-stage renal disease, strokes, trauma-related cases such as automobile accidents and gunshot wounds, and some mental disorders. The CHEF is intended to insulate the IHS and Tribal PRC operations from financial disruption caused by the intensity of expenses incurred as a result of high cost illnesses and/or disasters.
Disaster means a situation that poses a significant level of threat to life or health or causes loss of life or health stemming from events such as tornadoes, earthquakes, floods, catastrophic accidents, epidemics, fires, and explosions. The CHEF is intended to insulate the IHS and Tribal PRC operations from financial disruption caused by the intensity of expenses incurred as a result of high cost illnesses and/or disasters.
Episode of care means the period of consecutive days for a discrete health condition during which reasonable and necessary medical services related to the condition occur.
Purchased/referred care means any health service that is-
Service Unit means an administrative entity of the Service or a Tribal Health Program through which services are provided, directly or by contract, to eligible Indians within a defined geographic area.
Threshold cost means the annual designated amount above which incurred medical costs will be considered for the CHEF reimbursement after a review of the authorized expenses and diagnosis.
42 C.F.R. §136.501