California Code, Labor Code - LAB § 4604.5

(a) The recommended guidelines set forth in the medical treatment utilization schedule adopted by the administrative director pursuant to Section 5307.27shall be presumptively correct on the issue of extent and scope of medical treatment.  The presumption is rebuttable and may be controverted by a preponderance of the scientific medical evidence establishing that a variance from the guidelines reasonably is required to cure or relieve the injured worker from the effects of his or her injury.  The presumption created is one affecting the burden of proof.

(b) The recommended guidelines set forth in the schedule adopted pursuant to subdivision (a) shall reflect practices that are evidence and scientifically based, nationally recognized, and peer reviewed.  The guidelines shall be designed to assist providers by offering an analytical framework for the evaluation and treatment of injured workers, and shall constitute care in accordance with Section 4600 for all injured workers diagnosed with industrial conditions.

(d) For all injuries not covered by the official utilization schedule adopted pursuant to Section 5307.27, authorized treatment shall be in accordance with other evidence-based medical treatment guidelines that are recognized generally by the national medical community and scientifically based.