Thanks james
Looks like this is the relevant description.

(2) "Health care professional," for purposes of this chapter only,
27 means a physician licensed under chapter 18.71 RCW, a physician
28 assistant licensed under chapter 18.71A RCW, an osteopathic physician
29 licensed under chapter 18.57 RCW, an osteopathic physicians' assistant
30 licensed under chapter 18.57A RCW, a naturopath licensed under chapter
31 18.36A RCW, or an advanced registered nurse practitioner licensed under
32 chapter 18.79 RCW.