1. Except in cases of medical emergency, a person shall be admitted to a state mental health institute as an inpatient only after a preliminary diagnostic evaluation performed through the regional administrator for the person’s county of residence has confirmed that the admission is appropriate to the person’s mental health needs, and that no suitable alternative method of providing the needed services in a less restrictive setting or in or nearer to the person’s home community is currently available. If provided for through the regional administrator, the evaluation may be performed by a community mental health center or by an alternative diagnostic facility. The policy established by this section shall be implemented in the manner and to the extent prescribed by sections 225C.15, 225C.16, and 225C.17.
 2. As used in this section and sections 225C.15, 225C.16, and 225C.17, the term “medical emergency” means a situation in which a prospective patient is received at a state mental health institute in a condition which, in the opinion of the chief medical officer, or that officer’s physician or physician assistant designee, provided that a physician assistant designee meets the qualifications set forth in the definition of a mental health professional in section 228.1, requires the immediate admission of the person notwithstanding the policy stated in subsection 1.