Inpatient. A patient who has been admitted to a hospital or other authorized institution for bed occupancy for purposes of receiving necessary medical care, with the reasonable expectation that the patient will remain in the institution at least 24 hours, and with the registration and assignment of an inpatient number or designation. Institutional care in connection with in and out surgery is not included within the meaning of inpatient whether or not an inpatient number or designation is made by the hospital or other institution. If the patient has been received at the hospital, but death occurs before the actual admission occurs, an inpatient admission exists as if the patient had lived and had been formally admitted.
32 CFR § 199.2
General. In an effort to be as specific as possible as to the word and intent of CHAMPUS, the following definitions have been developed. While many of the definitions are general and some assign meaning to relatively common terms within the health insurance environment, others are applicable only to CHAMPUS; however, they all appear in this part solely for the purpose of the Program. Except when otherwise specified, the definitions in this section apply generally throughout this part.