California Code, Health and Safety Code - HSC § 1375.9

(a) A health care service plan shall ensure that there is at least one full-time equivalent primary care physician for every 2,000 enrollees of the plan. The number of enrollees per primary care physician may be increased by up to 1,000 additional enrollees for each full-time equivalent nonphysician medical practitioner supervised by that primary care physician.

(b) This section shall not require a primary care physician to accept an assignment of enrollees by a health care service plan without his or her approval, or that would be contrary to paragraph (2) of subdivision (b) of Section 1375.7.

(c) This section does not modify subdivision (e) of Section 2836.1 of the Business and Professions Code or subdivision (b) of Section 3516 of the Business and Professions Code.

(d) For purposes of this section, a primary care provider includes a “nonphysician medical practitioner,” which is defined as a physician assistant performing services under the supervision of a primary care physician in compliance with Chapter 7.7 (commencing with Section 3500) of Division 2 of the Business and Professions Code or a nurse practitioner performing services in collaboration with a physician pursuant to Chapter 6 (commencing with Section 2700) of Division 2 of the Business and Professions Code.