California UR and IMR: The Record and Deadlines After Treatment Is Denied

A procedural guide to treatment entitlement, utilization review, independent medical review, deadlines, and the administrative record in California workers’ compensation.

California separates a dispute over medical necessity from other disputes about liability or treatment. The procedural question is not simply whether care was “denied.” It is what the treating physician requested, who made the decision, why it was modified or denied, when the decision was served, and which review mechanism the statute assigns.

The treatment right begins with section 4600

Cal. Lab. Code § 4600 requires the employer to provide medical treatment reasonably required to cure or relieve the effects of the work injury. The statute ties reasonably required treatment to the guidelines adopted through the Medical Treatment Utilization Schedule. It also addresses treatment control, predesignation, travel expenses, interpreters, and other care-related subjects.

The DWC’s medical-care page explains that claims administrators use utilization review to decide whether to approve treatment recommended by the treating doctor. The procedural record should therefore begin with the physician’s request for authorization and the medical basis supporting it.

Identify exactly what utilization review decided

A UR notice may approve, modify, or deny a recommended service. Extract the treatment requested, diagnosis or condition addressed, stated medical-necessity rationale, decision date, service date, and instructions provided to the employee. Do not combine multiple requests or assume that a decision about one service resolves every treatment issue.

The operative documents usually include the treating physician’s request, the records submitted with it, the UR decision, and the notice sent to the worker. A later dispute cannot be evaluated reliably without knowing whether the reviewer saw the relevant history, findings, prior care, and clinical explanation.

Section 4610.5 assigns medical-necessity review to IMR

Cal. Lab. Code § 4610.5 applies to the treatment disputes described in the statute. It defines disputed medical treatment and provides that a UR decision modifying or denying care on medical-necessity grounds may be reviewed through independent medical review. For covered disputes, the UR decision may be reviewed or appealed only through IMR.

The DWC’s IMR page and official forms page provide current forms and administrative information. The UR notice should include the prescribed one-page form and addressed envelope or electronic instructions required by section 4610.5(f).

The deadline depends on the type of dispute

Section 4610.5(h) requires an IMR request within 10 days after service of a UR decision for formulary disputes and within 30 days after service for other medical-treatment disputes. If the employer does not provide the required notice and form, the statutory period does not begin until the required material is supplied. If another liability issue is being disputed at the same time, the statute contains a separate timing rule.

Record the service method and date rather than using the date the worker happened to read the notice. If a deadline is uncertain, obtain advice promptly; a general article cannot determine how service and any extension apply to a particular notice.

The IMR record is document-driven

Section 4610.5 gives the employee the right to provide information supporting medical necessity. The employee or physician may supply the recommendation, relevant medical information, urgent-care justification, and other reasonable material supporting the requested treatment. After assignment, the employer must transmit the categories of records identified in the statute and provide the employee and requesting physician with the required copies or list.

A record audit should answer four questions: Was the exact request for authorization included? Does the treating report explain why the service is medically necessary for this patient? Were relevant imaging, examination findings, prior treatment and response included? Does the transmittal list show what the reviewer received? Mission X’s guide to a medical report that omits disputed issues addresses a different medical-legal problem and should not be confused with IMR.

Not every treatment disagreement is a pure IMR question

Section 4610.5 addresses medical-necessity determinations. An employer may separately dispute industrial injury, body part, treatment responsibility, authorization, or another threshold issue. The same notice can reveal more than one ground. Identify each stated basis before deciding that IMR alone resolves the controversy.

For care during claim investigation, see the separate explanation of Riverside treatment and UR/IMR steps and the statutory rule in Cal. Lab. Code § 5402(c). Mission X’s Workers’ Compensation practice page describes the broader claim context.

Frequently Asked Questions

What makes a treatment dispute eligible for IMR?

Section 4610.5 covers the disputes listed in subdivision (a) and defines a medical-necessity denial or modification by utilization review. A different liability ground may require separate analysis.

Which IMR deadline applies?

The statute provides 10 days after service for formulary disputes and 30 days after service for other medical-treatment disputes, with additional rules when required notice is missing or another liability issue remains unresolved.

What belongs in the IMR record?

The requesting report, relevant medical history and findings, the UR decision, records considered, employee or physician submissions, and the employer’s statutory transmittal material should be accounted for. The value of a document depends on its relevance to the disputed service and medical necessity.

What to Do Next: Audit the Record

• Match the exact requested service to the UR disposition.
• Record the service date and the applicable statutory request period.
• Compare the treating report and supporting records with the employer’s transmittal list.
• Separate medical necessity from any injury, body-part, authorization, or other liability ground.

The Bottom Line

What this means for workers: A treatment-denial review begins with classification: the precise request, the UR ground, the service date, the applicable IMR period, and the contents of the administrative record. Separating those components prevents a medical-necessity dispute from being confused with a different threshold issue.

Related case analysis: Simmons: Utilization Review Does Not Decide Industrial Causation.