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Miguel Orellana
✦ Certified Specialist in Workers’ Compensation Law — Certified by the State Bar of California, Board of Legal Specialization ✦
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By Eman Yazdchi, Esq. · Certified Specialist in Workers' Compensation Law, State Bar of California Board of Legal Specialization
In California, Labor Code §4610 governs Utilization Review (UR) — the process by which a workers' compensation insurer reviews each requested treatment against the Medical Treatment Utilization Schedule. A UR denial can be appealed through Independent Medical Review under §4610.5. Yazdchi Law, a Certified Specialist in Workers' Compensation Law firm, handles California UR disputes statewide. Request a free case review.
Under California Labor Code §4610, Utilization Review (UR) is the process by which a California workers' compensation insurer reviews each treatment request from a treating physician against the Medical Treatment Utilization Schedule (MTUS) adopted by the Division of Workers' Compensation. The insurer's UR physician — who must be licensed in California in the same or a related specialty — issues a decision approving, modifying, or denying the requested treatment. UR exists to control treatment costs and to enforce evidence-based medicine; it is also the most common point at which California workers' compensation treatment is delayed or denied. For the statewide framework, see California workers' comp claim-denied playbook.
Under California Labor Code §4610, prospective UR — review of treatment requested but not yet provided — must be completed within five working days of the receipt of the request, extendable to 14 days if additional information is needed. Expedited UR for urgent treatment must be completed within 72 hours. Retrospective UR — review of treatment already provided — must be completed within 30 days. A California UR decision that exceeds these timeframes is void, and the requested treatment is deemed authorized. Related coverage: California back-injury workers' comp statewide pillar.
California Labor Code §4610 requires UR decisions to apply the Medical Treatment Utilization Schedule (MTUS), the official treatment guideline adopted by the Division of Workers' Compensation. The MTUS incorporates the ACOEM Practice Guidelines and the ODG Treatment in Workers' Comp Guidelines as the presumptively correct medical standard. A California UR decision that denies treatment must cite the specific MTUS provision that supports the denial.
A UR denial under California Labor Code §4610 is appealed through Independent Medical Review (IMR) under California Labor Code §4610.5. The injured California worker has 30 days from the UR denial to file an IMR application with the Department of Industrial Relations. IMR is decided by an independent physician on a Maximus Federal Services panel. The IMR physician applies the same MTUS standard but is independent of the workers' compensation insurer. An IMR decision is binding on the parties. Related coverage: California Labor Code §4610.5 (Independent Medical Review of UR denials).
When a California UR decision exceeds the timeframes set in California Labor Code §4610, the decision is procedurally invalid and the requested treatment is deemed authorized by operation of law. The Dubon v. World Restoration WCAB en banc decisions established that an untimely UR decision is jurisdictionally defective; the worker can move at the WCAB to enforce authorization rather than litigating the underlying medical necessity through IMR. Statute deep-dive: California Labor Code §4616 (Medical Provider Network).
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Tap to call →Last reviewed by Eman Yazdchi, Esq., May 2026.
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