(1) Each health benefit plan offered to public employees and their covered dependents under this chapter that is not subject to chapter 48.43 RCW and that is issued or renewed after December 31, 2015, must offer benefits or coverage for medically necessary elemental formula, regardless of delivery method, when a licensed physician or other health care provider with prescriptive authority:

(a) Diagnoses a patient with an eosinophilic gastrointestinal associated disorder; and

(b) Orders and supervises the use of the elemental formula.

(2) Nothing in this section prohibits a health benefit plan from requiring prior authorization or imposing other appropriate utilization controls in approving coverage for medically necessary elemental formula.