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✦ Certified Specialist in Workers’ Compensation Law — Certified by the State Bar of California, Board of Legal Specialization ✦
Serving injured workers across California. Board-certified specialist; no fee unless we win.
By Eman Yazdchi, Esq. · Certified Specialist in Workers' Compensation Law, State Bar of California Board of Legal Specialization
In California, Utilization Review (UR) is the insurer's process under §4610 for reviewing whether a workers' comp treatment request is medically necessary. UR decisions are made by a reviewing physician applying the Medical Treatment Utilization Schedule. Yazdchi Law, a Certified Specialist in Workers' Compensation Law firm, fights UR denials. Request a free case review.
For an injured California worker, "Utilization Review" is the gate every treatment recommendation has to pass through. The treating physician writes a Request for Authorization for an MRI, a steroid injection, physical therapy, or a surgery — and before the insurer pays, a reviewing physician decides whether the treatment matches the state's medical guidelines. A UR denial does not mean the treatment is wrong; it means one reviewer thought the paperwork did not support it.
This guide walks through how UR actually works under California law, what the Medical Treatment Utilization Schedule does, what the timelines are, and how an injured worker fights back when treatment is denied. It is written for a worker whose doctor just told them "the insurance company denied your treatment request."
The short version: UR is procedural, not personal. A clean Request for Authorization that ties to the MTUS gets authorized; one that does not gets denied. An attorney's job is often less about arguing the medicine and more about getting the paperwork into the right shape.
Utilization Review under California Labor Code §4610 is the process by which a California workers' compensation insurer (or the insurer's UR organization) reviews each treatment request to determine whether it is medically necessary. UR applies to every treatment that requires authorization beyond the initial $10,000 the insurer must authorize within one day of the completed DWC-1 under California Labor Code §5402(c).
The UR review is conducted by a physician licensed in any U.S. state who has clinical expertise in the treatment under review. The reviewing physician applies the Medical Treatment Utilization Schedule (MTUS) — California's evidence-based treatment guidelines published by the California Division of Workers' Compensation — to decide whether to approve, modify, deny, or delay the requested treatment. The MTUS covers most musculoskeletal, pain, neurological, and psychological conditions.
UR is governed by strict timelines. Missing a UR timeline often means the requested treatment is deemed authorized — which is a powerful argument for the worker.
For a non-urgent treatment request, the insurer must issue a UR decision within 5 working days of receipt of the Request for Authorization, with limited extensions. The decision is then served on the worker, the treating physician, and the worker's attorney. A UR decision that is not issued within the statutory window is generally not enforceable, and the treatment may be deemed authorized by operation of law.
For urgent treatment — where the worker's condition could reasonably jeopardize life, health, or ability to regain function — the insurer must issue an expedited UR decision within 72 hours of receipt of the request. The expedited timeline is real and enforceable; a delay can support a 25% penalty under California Labor Code §5814 for unreasonably delayed benefits.
For treatment that has already been provided, the insurer has 30 days from receipt of the bill to issue a retrospective UR decision. Retrospective UR is often used to deny treatment a worker received in emergency situations without prior authorization.
A valid UR denial letter must include specific information under California law: the clinical reasons for the denial, the specific MTUS guideline citations relied on, the name and credentials of the reviewing physician, the date of the request and the date of the decision, and detailed instructions for filing an Independent Medical Review (IMR) appeal under California Labor Code §4610.5. A UR denial letter that omits any of these is procedurally defective.
The IMR right is critical. Within 30 days of receipt of the UR denial under California Labor Code §4610.5, the worker can appeal to IMR, where an independent physician reviews the medical record and either upholds or overturns the denial. The IMR decision is binding with narrow appeal grounds.
A specialist attorney fights UR denials on four fronts. First, by working with the treating physician to write Requests for Authorization that explicitly cite MTUS guidelines, document failed conservative care, and include objective findings — imaging, exam findings, functional limitations. Second, by filing IMR appeals on the 30-day deadline and submitting supplemental medical evidence directly to the IMR organization. Third, by documenting patterns of unreasonable delay or repeated denials for treatment a QME or AME under California Labor Code §4062.2 has stated is necessary — which can support a California Labor Code §5814 penalty. Fourth, by challenging procedurally defective UR decisions directly at the WCAB.
An IMR overturn is binding and the treatment must be authorized. If the insurer fails to comply, the worker can file an enforcement motion at the WCAB and seek penalties under California Labor Code §5814 for unreasonably delayed benefits. Persistent post-IMR delays can also support a California Labor Code §132a retaliation petition if the pattern is tied to the worker's claim — providing reinstatement, lost wages, an increase in compensation of up to $10,000, and costs up to $250. After an adverse Findings and Award, a Petition for Reconsideration is filed within 25 days of service by mail (or 20 days from electronic service) under California Labor Code §5903.
California law does not require prior UR authorization for emergency medical treatment. Under California Labor Code §4600, the employer must provide all medical treatment reasonably required to cure or relieve the injury — emergency care for a work injury is owed regardless of prior authorization. Retrospective UR may later review the emergency care, but a defensible emergency-room visit is generally upheld. The worker should keep all bills, discharge instructions, and follow-up records, and let the attorney handle reimbursement or lien resolution.
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Tap to call →A UR denial letter has a 30-day clock on the back. The worker's three priorities are: file the IMR within the deadline, do not stop pursuing the underlying treatment, and get a free consultation before the appeal deadline.
Under California Labor Code §4610.5, the worker has 30 days from receipt of the UR denial to file the IMR application. The form is included with the UR denial letter and is also available from the California Division of Workers' Compensation at dir.ca.gov. A specialist attorney also reviews the UR denial for procedural defects — missing MTUS citations, missing reviewer credentials, missing IMR appeal instructions — that may invalidate the denial directly at the WCAB.
UR and IMR are records-based reviews. The single biggest determinant of an authorization is the quality of the medical record — objective findings, MTUS citations, documentation of failed conservative care, and clear functional limitations. A specialist attorney coordinates with the treating physician to write Requests for Authorization that align with the MTUS and include the evidence the reviewer needs to authorize.
California workers' compensation attorneys work on contingency under California Labor Code §4906 — typically 15% of any settlement, paid only if the case recovers. A free consultation costs nothing, and a Certified Specialist in Workers' Compensation Law, certified by the California Board of Legal Specialization, State Bar of California, can evaluate the UR denial and the IMR strategy. Yazdchi Law handles California UR and IMR disputes from the firm's office in Palmdale.
Last reviewed by Eman Yazdchi, Esq., May 2026.
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