Wash. Rev. Code § 48.20.525
Disability insurance companies who through an authorized representative have first approved, by any means, an individual prescription claim as eligible may not reject that claim at some later date. Pharmacists or drug dispensing outlets who obtain preapproval of claims shall keep a written record of the preapproval that consists of identification by name and telephone number of the person who approved the claim.
RCW 48.20.525
Findings-1993 c 253: "The legislature finds that many health care insurance entities are initially approving claims as eligible under an identified program, over the telephone, but denying those same claims when they are submitted for payment. The legislature finds this to be an untenable situation for the providers." [ 1993 c 253 s 1.]
Effective date-1993 c 253: "This act is necessary for the immediate preservation of the public peace, health, or safety, or support of the state government and its existing public institutions, and shall take effect immediately [May 7, 1993]." [ 1993 c 253 s 6.]