California Code, Civil Code - CIV § 56.37

(a) No provider of health care, health care service plan, or contractor may require a patient, as a condition of receiving health care services, to sign an authorization, release, consent, or waiver that would permit the disclosure of medical information that otherwise may not be disclosed under Section 56.10 or any other provision of law.  However, a health care service plan or disability insurer may require relevant enrollee or subscriber medical information as a condition of the medical underwriting process, provided that Sections 1374.7 and 1389.1 of the Health and Safety Code are strictly observed.

(b) Any waiver by a patient of the provisions of this part, except as authorized by Section 56.11 or 56.21 or subdivision (b) of Section 56.26, shall be deemed contrary to public policy and shall be unenforceable.