CA Ins Code §10123.135(h)(1)

(h) In determining whether to approve, modify, or deny requests by providers prior to, retrospectively, or concurrent with the provision of health care services to insureds, based in whole or in part on medical necessity, every insurer subject to this section shall meet the following requirements:

(1) Decisions to approve, modify, or deny, based on medical necessity, requests by providers prior to, or concurrent with, the provision of health care services to insureds that do not meet the requirements for the time period for review required by paragraph (2), shall be made in a timely fashion appropriate for the nature of the insured’s condition, not to exceed five business days from the insurer’s receipt of the information reasonably necessary and requested by the insurer to make the determination.