Wash. Rev. Code § 48.21.142
Notwithstanding any provision of any group disability insurance contract or blanket disability insurance contract as provided for in this chapter, benefits shall not be denied thereunder for any health service performed by a holder of a license issued pursuant to chapter 18.25 RCW if (1) the service performed was within the lawful scope of such person's license, and (2) such contract would have provided benefits if such service had been performed by a holder of a license issued pursuant to chapter 18.71 RCW: PROVIDED, HOWEVER, That no provision of chapter 18.71 RCW shall be asserted to deny benefits under this section.
The provisions of this section are intended to be remedial and procedural to the extent they do not impair the obligation of any existing contract.
RCW 48.21.142