California’s physician assistant (“PA”) practice landscape is set to undergo significant transformation following the enactment of California Assembly Bill 1501 (AB 1501), which was signed into law by Governor Newsom on October 1, 2025, and will take effect on January 1, 2026. Among its key provisions, AB 1501 extends the authority of the California Department of Consumer Affairs’ Physician Assistant Board (the “Board”) through January 1, 2030, increases the physician-to-PA supervision ratio from 1:4 to 1:8 in all settings, and directs the Board to study scope-of-practice structures—with input from stakeholders—to evaluate potential models from other states that could benefit California. These modernization efforts are designed to enhance healthcare access and better align PA practice with current workforce demands. This article summarizes the key reforms implemented by AB 1501 and offers guidance on how PAs and their practices can prepare for these new requirements.
Current Legal Framework
Although PAs play a vital role in care delivery, their authority is subject to certain limitations. California law sets out specific rules on the scope of PA practice, supervision requirements, and the circumstances under which PAs may diagnose, treat, or prescribe. PAs must only provide services they are competent to perform, based on their education, training, and experience. Further, PAs must practice under a practice agreement with a supervising physician (MD or DO), which expressly sets out the PA’s medical services, supervision protocols (direct or indirect), and any prescribing or treatment limitations.[1]
Current laws impose a 1:4 physician-to-PA supervision ratio in most settings, with an increased ratio of 1:8 allowed for PAs who perform in-home health evaluations. [2] The supervising physician is required to maintain a current, unrestricted license and must be readily available for consultation—whether by phone or electronic communication—when the PA is treating patients.[3] Collectively, these rules are intended to protect patient safety while enabling PAs to operate within a regulated structure.
Key Reforms Under AB 1501
AB 1501’s legislative amendments are codified under the California Business and Professions Code. The bill introduces several important changes to California’s PA practice such as:
- Expanded Supervision Ratios: AB 1501 increases the number of PAs that a physician (MD or DO) may supervise at any time from 4 to 8 across all practice settings. This amendment also removes the previous exception for PAs exclusively performing in-home health evaluations, creating a uniform supervision ratio of 1:8 statewide.
- Comprehensive Review of Practice Agreements: The Board is required to conduct a thorough review of practice agreement structures, in consultation with relevant stakeholders. This review will examine the utilization and impact of practice agreements in other states and assess potential benefits or drawbacks for patient care, workforce efficiency, and regulatory oversight in California. Certain key stakeholders, such as the California Academy of Physician Associates (“CAPA”), participated in several meetings with the Board to discuss the current state of PA practice in California and its impact on healthcare access relative to other states. CAPA highlighted the significance of the reform, noting that, “while many other states have waived the ratio entirely, doubling here in California represents real progress that will immediately benefit patients.”[4]
- Extension of PA Board Operations: The bill extends the operation of the Board—which oversees PA licensing and regulation—through January 1, 2030.
- Updated Licensing Fees: AB 1501 establishes certain new and increased application and license fees for PAs, while also setting maximum fee limits for certain types of licenses and application fees.
- Electronic License Renewals: PA license renewal applications will now be required to be submitted via an electronic form, or other form, as provided by the Board.
Next Steps
With the recent enactment of AB 1501, PAs and their practices may consider the following:
- Review current supervision structures and practice agreements to identify all PAs and assess existing supervisory ratios to ensure compliance with the new 1:8 physician-to-PA limit, regardless of care setting.
- Revisit practice agreements to ensure roles, PA duties, and supervision protocols remain clear and are updated in line with the evolving Board guidance.
- With the implementation of a greater PA ratio, PAs and supervising physicians should maintain thorough documentation and clear communication, particularly during the transition period, to ensure correct monitoring and maintain appropriate standards of patient care.
- Supervising physicians and PAs should proactively review their insurance coverage in light of the new supervision ratios and other changes introduced by AB 1501 to ensure continued protection and compliance.
- Practices and PAs should stay actively informed about potential updates to PA practice regulations and additional Board guidance regarding practice agreements.
Conclusion
In sum, AB 1501 marks a significant shift in the practice landscape for California PAs, introducing greater supervisory flexibility and modernizing regulatory frameworks. Now that AB 1501 has been signed into law, practices and PAs should remain actively informed about its provisions and monitor any further implementation guidance issued by the Board. We will continue to monitor legislative and regulatory developments closely and provide updates as new information becomes available.
FOOTNOTES
[1] Cal. Bus. & Prof. Code §§ 3501(k); 3502.3.
[2] Id. at § 3516.
[3] Id. at 3502.
[4] Cal. AB 1501, Assembly Floor Analysis, dated September 10, 2025, pg. 4.