When Your Workers' Comp Claim Is Denied for a "Lack of Evidence" in California

Few things are more frustrating than getting hurt at work, following every rule, and then receiving a letter that says your claim is denied for a "lack of evidence." You know what happened. Your body knows what happened. But a claims examiner, reading a thin file from a desk somewhere, decided the paperwork didn't add up.

That denial is not the end of your case. In California, it is the beginning of a process with deadlines, appeal rights, and independent review—all of which favor the worker who moves quickly.

What "Lack of Evidence" Actually Means

When a carrier denies for insufficient evidence, it is almost never saying you weren't hurt. It is saying one of the following:

• The medical record doesn't clearly connect your condition to your job duties.
• A required report—a progress report, a diagnostic study, a treating physician's opinion—isn't in the file.
• Utilization Review found the requested treatment wasn't supported by the applicable guidelines.
• The carrier believes a prior injury or a non-work cause explains your condition.

Each of these is answerable. But each is answered with documents, filed within deadlines.

Related Article: How to Appeal a Workers' Comp Denial

Utilization Review vs. Claim Denial

It is worth separating two things injured workers often confuse.

A claim denial rejects the compensability of the injury itself. A Utilization Review (UR) non-certification accepts the claim but denies a specific requested treatment. Both feel like being told no. They have completely different appeal routes.

UR decisions are appealed through Independent Medical Review (IMR)—a review by an outside physician who has no relationship with the insurance carrier. And IMR runs on a clock. Under California law the application is generally due within 30 days of the UR determination, and in some cases as few as 10 — the applicable deadline is printed on the UR letter and on the IMR application form itself. Miss it and the denial stands, regardless of how wrong it was.

Related Article: Workers' Compensation Keeps Denying Medical Treatment

Case Study: Everything Denied on March 28. Everything Overturned by April 28.

The following is drawn from an actual SoCal Workers Comp file. All identifying details—names, employers, case numbers, and locations—have been changed or withheld to protect our client's privacy.

The Client: An Accepted Lumbar Spine Injury

A 41-year-old school district employee with an accepted lumbar spine injury from October 2019.

The Documented Condition: Imaging, Exam Findings, and Failed Conservative Care

By early 2023 the medical record was not ambiguous. MRI showed a large central disc herniation at L5-S1. Examination showed positive bilateral straight leg raise and diminished sensation. Conservative care—medication, therapy—had not resolved the radicular symptoms. Her treating physician requested transforaminal epidural steroid injections, eight post-injection physical therapy visits, and the pre-procedure COVID test the facility required.

The Denial: Utilization Review Non-Certified Every Single Item

On March 28, 2023, the carrier's Utilization Review non-certified every single item. Not one modification. Not a partial approval. The injections, the therapy, and even the COVID test required to enter the procedure suite were all denied.

Our Response: The IMR Application Filed in Two Days

We filed the Independent Medical Review application on March 30, 2023—two days after the denial, well inside the filing window. We submitted the supporting record with it: the imaging, the objective examination findings, the documented failure of conservative treatment, and the MTUS guideline support for epidural steroid injections in radiculopathy confirmed by imaging.

The IMR Determination: Overturned on Every Disputed Item

On April 28, 2023, the Independent Medical Review organization issued its Final Determination Letter. The reviewing physician overturned the denial on every disputed item. The injections: medically necessary. The eight physical therapy visits: medically necessary. The COVID test: medically necessary.

The Carrier's Capitulation

On May 4, 2023, the carrier issued its Notice of Administrative Authorization, authorizing all of it.

The Arithmetic: 31 Days From Denial to Full Reversal

Total denial to full reversal: 31 days. Denied items overturned: all of them. What made it possible was not an argument. It was a complete record filed inside the deadline.

The Uncomfortable Counterfactual

Had she done nothing for 31 days—which is an entirely reasonable amount of time for a person in pain to spend being angry, confused, or waiting for someone to call her back—the IMR window would have closed. The same treatment an independent physician found medically necessary would simply not have happened. And the treatment denial could remain in effect for an entire year.

Why the Deadline Is the Whole Ballgame

Insurance carriers are not required to remind you that your appeal rights are expiring. The UR letter states the deadline, usually in dense type on a later page, and then the burden shifts entirely to you.

This is the single most common way meritorious claims die in California workers' compensation: not by losing, but by lapsing.

If you have received a denial of any kind—claim denial, UR non-certification, a delay letter that never resolves—calendar the deadline the day you receive it and get the file in front of someone who does this daily.

Related Article: How to Appeal a Denied Workers' Compensation Claim in California: A Complete Checklist

What Our Clients Say About Fighting Denials

Denials are the most common frustration our clients bring us. Here is how they've described the experience in their own words on Google:

"So far so good it's a process and it gets frustrating at times because the insurance company denies everything but my attorney responds fast and answers all my questions and keeps me up to date and in the loop" — Edward O., 5-star Google review

"Whenever I received any letter or any sudden deadline from the insurance company for what I perceived as attempts by them to make my path more difficult and add unnecessary pressure and stress to my life. All I had to do was contact my SoCal workman's Comp attorney … and he would take it from there. He would speak directly to the defense in the same day and his experience and knowledge allowed him to navigate and remove the attempts by the insurance company to place obstacles in front of my path like the ever common denial of surgery." — Rocko R., 5-star Google review

A Denial Is a Position, Not a Verdict

A claims examiner denying your treatment is not a judge ruling against you. It is one party in a dispute taking a position. California built IMR, the expedited hearing, and the WCAB precisely because that position is often wrong.

Related Article: Navigate Your Workers Comp Denial Letter with Help from Workers Comp Attorneys

Talk to SoCal Workers Comp

If your claim or your treatment has been denied for a "lack of evidence," bring us the letter. We will identify what the file is actually missing and take the appropriate action.

Consultations are free, and we represent injured workers on a contingency basis—there is no fee unless we recover for you.

Case study details are drawn from actual matters handled by SoCal Workers Comp, with all client, employer, and case-identifying information changed or withheld. Past results do not guarantee a similar outcome in any other case. Client testimonials are reproduced verbatim from the firm's public Google Business Profile reviews (5.0 stars, 85 reviews as of August 2026) and are not a guarantee of results. This article is general information, not legal advice.