California Code, Evidence Code - EVID § 994

(a) The holder of the privilege;

(b) A person who is authorized to claim the privilege by the holder of the privilege; or

(c) The person who was the physician at the time of the confidential communication, but such person may not claim the privilege if there is no holder of the privilege in existence or if he or she is otherwise instructed by a person authorized to permit disclosure.

The relationship of a physician and patient shall exist between a medical or podiatry corporation as defined in the Medical Practice Act and the patient to whom it renders professional services, as well as between such patients and licensed physicians and surgeons employed by such corporation to render services to such patients. The word “persons” as used in this subdivision includes partnerships, corporations, limited liability companies, associations, and other groups and entities.