In this guide9 sections
Labor Code §4610 sets the rules for utilization review (UR), the process California workers’ comp insurers use to approve, modify or deny the treatment your doctor requests. UR has strict deadlines, generally five business days for a routine request and 72 hours when your health is in serious danger, and only a licensed physician can deny care as not medically necessary. If UR denies or changes your treatment, your next step is usually Independent Medical Review (IMR), which you generally must request within 30 days.
Key takeaways
- Your treating doctor asks for treatment with a Request for Authorization (RFA). UR then decides whether it is medically necessary, using the Medical Treatment Utilization Schedule (MTUS).
- Routine UR decisions are due within five normal business days after the request and needed information, and never more than 14 days after the recommendation. Urgent requests must be decided within 72 hours.
- Only a licensed physician can modify, delay or deny treatment for medical necessity, and reviewers can’t be paid incentives based on denials.
- To challenge a UR denial or modification, you generally must request IMR within 30 days after the decision is served on you.
- For injuries on or after January 1, 2018, much of the care in the first 30 days is authorized without prospective UR.
What Labor Code §4610 does
Under Labor Code §4600, your employer must provide treatment reasonably required to cure or relieve the effects of your work injury. Section 4610 lets the employer or insurer review your doctor’s requests before, during or after treatment to decide whether they are medically necessary. In plain English, UR is the insurer’s gatekeeper, and §4610 sets the rules it has to follow. Your doctor starts the process by sending a Request for Authorization (RFA).
Every employer must have a UR program with written policies and a licensed medical director. The review criteria must be developed with practicing physicians, be consistent with the MTUS and drug formulary, be evaluated at least annually and be disclosed to you and your doctor when they are used to deny care. Learn how the guidelines work in our explainer on the Medical Treatment Utilization Schedule.
UR deadlines under §4610(i)
| Type of request | Deadline for a UR decision or notice |
|---|---|
| Routine (prospective or concurrent) request | Within 5 normal business days after the request and the information reasonably needed, and no more than 14 days from the doctor’s recommendation |
| Imminent and serious threat to your health | Within 72 hours after receiving the information needed |
| Retrospective review (care already given) | Within 30 days of receiving the information needed |
| Notice of decision to your doctor | No more than 24 hours after the decision, by phone, fax or agreed secure email |
| Written notice of a denial or modification | No more than 24 hours for concurrent review, or 2 business days for prospective review, to you and your doctor |
If the reviewer needs more information, it must immediately tell you and your doctor in writing what is missing. The clock then runs from when that information arrives.
Deadlines matter. In a 2014 en banc decision, the Workers’ Compensation Appeals Board held that a UR decision is invalid if it is untimely. In that case, a workers’ comp judge may decide whether the treatment is medically necessary, based on substantial medical evidence.
The first 30 days after an injury
For injuries on or after January 1, 2018, §4610(b) says that treatment for an accepted body part or condition within 30 days of the injury is authorized without prospective UR when it is consistent with the MTUS and comes from an MPN doctor, a predesignated physician, an employer-selected doctor where there is no MPN, or emergency care. Some services still need prior review even in that window, including nonemergency surgery, psychological treatment, home health care, imaging other than x-rays, durable medical equipment over $250, electrodiagnostic testing and drugs not on the formulary.
Who can deny your treatment
Only a licensed physician competent to evaluate the specific clinical issues may modify, delay or deny a request for medical necessity reasons. Non-physician reviewers can approve requests, but can’t deny them on medical grounds. The employer also may not offer reviewers any financial incentive based on the number of modifications or denials.
A UR denial generally stays in effect for 12 months for the same treatment from the same doctor, unless there is a documented change in material facts. UR isn’t required while the employer is disputing liability for the body part or condition.
If UR denies or modifies your treatment
- Read the denial letter. It should explain the reason, the criteria used and how and when to request IMR.
- Request IMR within 30 days. Under Labor Code §4610.5, you generally have 30 days after service of the UR decision. Your doctor can help by sending supporting records. The employer pays for IMR, as explained on the DWC’s IMR page.
- Ask your doctor to resubmit if facts change. New test results or a worsening condition can justify a new RFA.
- Check whether UR was late. An untimely decision may let a judge decide the treatment issue instead. If care is being held up, you may be able to request an expedited hearing.
IMR decisions are generally due within 30 days, or 3 days for expedited reviews. The IMR doctor reviews records and doesn’t examine you. The decision is binding and can be appealed to the Workers’ Compensation Appeals Board only on narrow grounds, within 30 days. See our guide to Independent Medical Review.
A hypothetical example
Teresa, a home health aide, injured her lower back lifting a patient. Two months later her treating doctor submits an RFA for a lumbar MRI. UR denies it on day six, saying conservative care hasn’t been tried long enough. Teresa receives the written denial with instructions for requesting IMR. She files the IMR request within 30 days, and her doctor sends therapy notes showing six weeks of failed physical therapy. The IMR reviewer can overturn the denial if the records show the MRI is medically necessary under the guidelines.
Frequently asked questions
Can the insurer deny my treatment without a doctor seeing me?
Yes. A UR physician reviews records, not you. But only a licensed physician can deny care for medical necessity, and the decision must follow the MTUS and the statutory deadlines.
How long does UR take?
Generally up to five normal business days after the insurer has the information it needs, and no more than 14 days from your doctor’s request. Urgent requests must be decided within 72 hours.
What happens if I miss the 30-day IMR deadline?
The UR decision generally stands. Your doctor may be able to submit a new request if your condition or the medical facts change.
Is UR the same as a QME?
No. UR and IMR decide whether specific treatment is medically necessary. QMEs and AMEs address other medical disputes, such as whether the injury is work-related and your permanent disability rating.
Can I get treatment on my own if UR denies it?
You can, but the insurer generally won’t pay for it unless the denial is overturned. Talk to a lawyer before paying out of pocket.
Talk to a California workers’ comp lawyer
Employees First Labor Law represents workers exclusively, including injured workers whose treatment has been delayed or denied through UR. We offer free virtual consultations to review your denial letters and deadlines. Contact us online or call (310) 853-3461.
This article is general information about California law as of 2026, not legal advice for your situation. Reading it does not create an attorney-client relationship.
