Cal. Lab. Code § 5307.6

(a) The administrative director shall adopt and revise a fee schedule for medical-legal expenses as defined by Section 4620, which shall be prima facie evidence of the reasonableness of fees charged for medical-legal expenses at the same time he or she adopts and revises the medical fee schedule pursuant to Section 5307.1.
The schedule shall consist of a series of procedure codes, relative values, and a conversion factor producing fees which provide remuneration to physicians performing medical-legal evaluations at a level equivalent to that provided to physicians for reasonably comparable work, and which additionally recognizes the relative complexity of various types of evaluations, the amount of time spent by the physician in direct contact with the patient, and the need to prepare a written report.
(b) A provider shall not be paid fees in excess of those set forth in the fee schedule established under this section unless the provider provides an itemization and explanation of the fee that shows that it is both a reasonable fee and that extraordinary circumstances relating to the medical condition being evaluated justify a higher fee; provided, however, that in no event shall a provider charge in excess of his or her usual fee. The employer and employee shall have standing to contest fees in excess of those set forth in the fee schedule.
(c) In the event of a dispute between the provider and the employer, employee, or carrier concerning the fees charged, the provider may be allowed a reasonable fee for testimony if the provider testified pursuant to the employer’s or carrier’s subpoena and the judge or referee determines that the fee charged was reasonable and justified by extraordinary circumstances.
(d)
1. (1) No provider may request nor accept any compensation, including, but not limited to, any kind of remuneration, discount, rebate, refund, dividend, distribution, subsidy, or other form of direct or indirect payment, whether in money or otherwise, from any source for medical-legal expenses if such compensation is in addition to the fees authorized by this section. In addition to being subject to discipline pursuant to the provisions of subdivision (k) of Section 139.2, any provider violating this subdivision is subject to disciplinary action by the appropriate licensing board.
2. (2) This subdivision does not apply to medical-legal expenses for which the administrative director has not adopted a fee schedule.