California UR and IMR deadlines: a guide for applicant attorneys

When a treating doctor asks for surgery, therapy or a medication, the claims administrator sends the request through utilization review (UR). If UR denies or modifies it, the only way to challenge that medical-necessity decision is independent medical review (IMR). Labor Code 4610.5(e) says so directly. The deadlines are short and some changed on April 1, 2026, so this guide sets out the current timeline. It is general information, not legal advice.

How UR and IMR fit together

The sequence is fixed:

1. The treating physician submits a Request for Authorization (RFA).
2. The claims administrator runs UR, or defers it if liability for the injury or body part is disputed.
3. UR approves, modifies or denies, and must tell the doctor and serve a written decision.
4. If the decision denies or modifies the treatment for medical necessity, the employee may request IMR.
5. Maximus Federal Services, the DWC's IMR organization, decides.
6. A party may appeal the IMR determination to the WCAB only on narrow grounds.

Disputes about whether the injury or body part is industrial are not IMR issues. Those go through the med-legal process described in our QME and AME guide.

UR timeframes

New UR and IMR regulations took effect on April 1, 2026. They implement SB 1160 and AB 1124 (formulary drugs) and split the old 8 CCR 9792.9.1 into sections 9792.9.1 through 9792.9.8. The current timeframes:

Receipt rules matter when you check the math. Under 8 CCR 9792.9.1, a fax, email or electronic RFA received after 5:30 p.m. Pacific counts as received the next business day, and a mailed RFA counts as received five business days after mailing.

The IMR request deadline

Under Labor Code 4610.5(h) and 8 CCR 9792.10.1:

The employee, the employee's attorney or a designee may file the request. The form is DWC Form IMR (revised April 1, 2026), with a copy of the UR decision, sent to the Administrative Director or its designee by mail, fax or electronically. An expedited request needs the treating physician's certification.

Count from service of the written decision, not from the date your client mentions it. When a UR denial lands, put both the 30-day date and the service date on the case.

After IMR is requested

The applicant side can submit records too. A short cover letter that tells the reviewer which guideline supports the request and attaches the doctor's reasoning is often the most useful thing a firm adds.

Appealing an IMR determination

Under Labor Code 4610.6(h), a verified appeal must be filed with the WCAB and served within 30 days of the date the determination was mailed. The determination is presumed correct and can be set aside only on clear and convincing evidence of one of five grounds:

1. The Administrative Director acted without or in excess of its powers.
2. The determination was procured by fraud.
3. The reviewer had a material conflict of interest.
4. The determination came from bias based on race, sex, religion, disability or another listed characteristic.
5. The determination rests on a plainly erroneous finding of fact that is a matter of ordinary knowledge, not expert opinion.

Disagreeing with the reviewer's medical judgment is not one of the grounds. If the WCAB reverses, the dispute goes back for review by a different reviewer or organization.

The 12-month rule and resubmitting

A UR decision to modify or deny stays effective for 12 months from the date of the decision for later requests for the same treatment, unless the new request is supported by a documented change in the facts material to the original decision (Labor Code 4610(k)). If IMR upholds a denial, the practical path is often a new RFA once the facts have changed, such as failed conservative care, new imaging or a new diagnosis, with that change written into the request.

Checklist when a UR denial arrives:

• Record the date of the decision and the date and method of service.
• Calendar the IMR deadline: 30 days, or 10 for a formulary drug.
• Check the notice for required content; a defective notice may delay the clock.
• Ask the treating doctor for a supporting report if the denial cites missing information.
• File the IMR application with the UR decision attached, and keep proof.
• Calendar the 30-day IMR decision window and follow up if it passes.

Building the record for IMR

IMR is decided on paper, so the result depends on what the reviewer receives. The claims administrator sends its file, but it may not include everything that supports the request. Before or with the application:

• Get the treating doctor's Request for Authorization and the report behind it, and check that the report explains why the treatment is needed for this patient.
• Find the guideline the doctor relied on. Many denials cite the Medical Treatment Utilization Schedule (MTUS) and say the request falls outside it; a doctor's report that addresses the guideline directly is more useful than one that ignores it.
• Gather the history that shows conservative care was tried: therapy notes, medication trials, injections, imaging.
• Check that the UR decision addressed the treatment actually requested. A modification to fewer visits or a different drug is still a decision you can take to IMR.
• Keep the client informed. A denied surgery is the kind of news that leads to calls, and the timeline above gives them realistic dates.

If the treatment is urgent, ask the doctor whether an expedited request is justified, since that needs the physician's certification and shortens every later deadline.

How a firm can track this

Every RFA has a life: submitted, decided, served, appealed. A spreadsheet works for a few cases; at volume, firms need each treatment request on the case with its status and the next deadline computed from the service date.

PlaintiffStack's workers' comp pages keep treatment requests on an Authorizations page, and a morning check lists IMR deadlines after a UR denial so they surface before they pass. A person still files the IMR application; the product doesn't submit it. Deadlines land on the firm calendar and tasks.