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Guides / Treatment denied (UR/IMR)
Guide · 5 min read · Published · Updated

Workers’ Comp Denied Your Surgery or Treatment? UR and IMR, Explained

What to do when California workers’ comp denies treatment: how utilization review actually works, the 5-day and 72-hour clocks, the 30-day IMR appeal window, why most denials trace back to the paperwork in the request — and where the real leverage is.

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No moment in a comp claim produces more fury than the letter denying the surgery your own doctor ordered — or the MRI, or the physical therapy. The system that produced it is utilization review — and beating it is about paperwork mechanics, not volume. Here is the machine, plainly.

Every request passes through UR

The treating doctor submits a request for authorization (DWC Form RFA); the claims administrator’s UR program answers on a clock — 5 business days for ordinary requests, 72 hours expedited (§4610). The reviewer is a physician applying the MTUS, California’s evidence-based treatment schedule. This is the part nobody tells injured workers: UR approves most requests. The denials cluster where the RFA is thin — no imaging attached, no documented failure of conservative care, no guideline citation.

The denial letter starts a 30-day clock

Appeal is independent medical review — the application ships with the denial, and you have 30 days to file (§4610.5; 10 days for a drug-formulary dispute). IMR is anonymous, paper-only, and binding (§4610.6): a state-contracted physician applies the same MTUS to whatever records are in the file. Most denials survive it — the DWC’s own IMR annual report puts 2025’s overturn rate at 10.2% (down from 12.7%), with program services (18.5%), behavioral-health (18.3%) and evaluation-and-management (16.8%) requests flipping most often (distilled with the category table in our state-data brief). The realistic wins come from two places: UR got the guidelines wrong, or the file was missing records that IMR now gets to see. Which is why the smart response to a denial is often a resubmitted RFA with changed facts — new imaging, progressed symptoms — since a denial only holds 12 months absent changed circumstances.

What UR cannot touch

UR governs treatment. It has no power over your rating — the WPI, apportionment, and work restrictions live in the med-legal lane with the QME, and the money math runs on the calculator regardless of what UR thinks of your surgery. Denied care also doesn’t erase the future-medical award: the award survives; each request still runs the UR gauntlet. Doctor choice upstream of all this: the MPN rules.

Estimates for informational use; not legal or medical advice.

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FAQ

What do I do if workers’ comp denies my surgery?
The denial letter is a utilization-review decision, and it comes with an IMR application — you have 30 days to file it (§4610.5). Independent medical review is a paper fight: the reviewer applies the MTUS treatment standards to the records submitted, so the move that actually changes outcomes is a treating doctor who resubmits with better documentation — imaging, failed conservative care, guideline citations — not an angrier appeal.
How long does utilization review take?
Prospective UR decisions are due within 5 business days of the request for authorization (expedited: 72 hours when delay threatens health). A denial generally holds for 12 months absent a documented change in facts — which is why the response to a denial is new facts, not the same request again.
Can I win an IMR appeal?
Most UR denials survive IMR — the state’s reviewers overturned just 10.2% of the UR denials decided in 2025, down from 12.7% the year before, per the DWC’s IMR annual report. The categories that flip most often run higher: program services (18.5%), behavioral and mental health services (18.3%), and evaluation-and-management requests (16.8%). Wins come from requests the UR reviewer got wrong on the guidelines or records the UR never saw, so the highest-leverage document in the whole process is the original request for authorization.

Sources

  1. IMR annual report · dir.ca.gov

About this guide. Rating and dollar figures here are computed with — or checked against — RateString’s rating engine, which reproduces the State’s own published worked examples (see the proof). Where the guide relies on a statute or regulation, it cites it in the text. Descriptive information, not legal advice. See something wrong? Report an error.