For individual and small group plans, the issuer must not exclude a category of provider who is licensed to provide services for a covered condition, and is acting within the scope of practice, unless such services would not meet the issuer's standards pursuant to RCW 48.43.045(1)(a). For example, if the issuer covers outpatient treatment of lower back pain as part of the essential health benefits, any category of provider that provides cost-effective and clinically efficacious outpatient treatment for lower back pain within its scope of practice and otherwise abides by standards pursuant to RCW 48.43.045(1)(a) must not be excluded from the network.
Wash. Admin. Code § 284-170-270