Washington Revised Code Title 48. Insurance § 48.200.250. Evidence of validation of claim

(1) An electronic or physical copy of a valid prescription if the prescribed drug was, within fourteen days of the dispensing date:

(2) Point of sale electronic register data showing purchase of the prescribed drug, medical supply, or service by the patient or the patient's designee; or

(3) Electronic records, including electronic beneficiary signature logs, electronically scanned and stored patient records maintained at or accessible to the audited pharmacy's central operations, and any other reasonably clear and accurate electronic documentation that corresponds to a claim.