Wash. Rev. Code § 18.200.020
An orthotist or prosthetist may only provide treatment utilizing new orthoses or prostheses for which the orthotist or prosthetist is licensed to do so, and only under an order from or referral by an authorized health care practitioner. A consultation and periodic review by an authorized health care practitioner is not required for evaluation, repair, adjusting, or servicing of orthoses by a licensed orthotist and servicing of prostheses by a licensed prosthetist. Nor is an authorized health care practitioner's order required for maintenance of an orthosis or prosthesis to the level of its original prescription for an indefinite period of time if the order remains appropriate for the patient's medical needs.
Orthotists and prosthetists must refer persons under their care to authorized health care practitioners if they have reasonable cause to believe symptoms or conditions are present that require services beyond the scope of their practice or for which the prescribed orthotic or prosthetic treatment is contraindicated.
RCW 18.200.020