PA · Washington
Collaborative Drug Therapy Management for Physician Assistants in Washington
Yes, a written agreement with a physician is required before you prescribe and adjust drug therapy. Washington calls it a Supervisory Practice Agreement.
HB 2041 (eff. Jan. 1, 2025) replaced WA's prior supervision-only model with a two-tier system: below the hours threshold, a 'participating physician' supervises per RCW 18.71A.030; above it, the relationship becomes 'collaboration' — consult/refer as indicated, no supervision requirement. Even post-threshold, a filed practice agreement is still required.
Independent practice requires: ≥4,000 hours of postgraduate clinical practice, including ≥2,000 hours in the PA's chosen specialty (a PA changing specialties must complete the first 2,000 hours in the new specialty back under supervision).
What the physician relationship must look like
The rules the physician relationship has to follow. Each fact comes from the statute or board rule listed under sources.
Proximity
below the 4,000-hour supervision tier: Available remotely (no on-site requirement)
The participating physician need not be physically present but must remain 'accessible and involved in the oversight structure' (secondary-sourced characterization of RCW 18.71A.030/.120 — no fixed mile/minute radius located in the statute itself).
Supervision ratio
Not codified — no cap on file
Chart review
Not codified — left to the agreement
Meeting cadence
Not codified — left to the agreement
Prescriptive authority
Separate prescribing terms required · controlled substances permitted
Prescribing must fall within the scope of the participating/collaborating physician's own clinical practice, as set out in the filed practice agreement (RCW 18.71A.120). No schedule-specific numeric limit was located in statute.
Written agreement
Required
Practice ownership (corporate practice of medicine)
Licensee-only ownership required — Professional Service Corporation under RCW 18.100 — Washington courts have affirmatively adhered to a corporate-practice-of-medicine doctrine (WA Supreme Court, 2010), but RCW 18.100.050(5)(a) permits a single multi-discipline PSC co-owned across 12 enumerated health professions including physicians, and RCW 18.71A.120(8) explicitly authorizes a licensed PA to independently own a healthcare clinic — a materially more permissive PA-ownership rule than most CPOM states on file.
Ownership eligibility (RCW 18.100) is legally distinct from the clinical supervision/collaboration tier above.
Sources for the supervision rules (5)
- RCW 18.71A.120 — Practice Agreement, Elements, Amendment, Disciplinary Action
- RCW 18.71A.030 — Supervision of Physician Assistantsecondary
- RCW 18.100 — Professional Service Corporation Act
- HB 2041 (2024, eff. Jan. 1, 2025) — PA supervision/collaboration reform
- Collaborating Physician — Washington Collaborating Physician Requirements & Compliance Rules (2026 Guide) [secondary source, used for the proximity/accessibility characterization]secondary
What a collaborating physician costs here
Typical monthly cost in Washington
$500 – $600
Estimate for one Physician Assistant. Standard-tier state.
About Washington's rules
Washington is a full-independence state for ALL FOUR ARNP roles (NP, CRNA, CNM, CNS) under RCW 18.79, not just NPs — confirmed current via WAC 246-840-300/420 and Board of Nursing guidance. PAs are separate: HB 2041 (eff. Jan. 1, 2025) replaced supervision-only with a 4,000-hour supervision→collaboration tier (RCW 18.71A.120) with no numeric ratio cap.
Other clinicians in Washington: see the state overview.