Medical Treatment Utilization Schedule (MTUS): Formulary, Reviews, and Appeals

California’s Medical Treatment Utilization Schedule, known as the MTUS, is the binding set of evidence-based rules that decides what medical care an injured worker receives through the state’s workers’ compensation system. It is codified at Title 8, California Code of Regulations, Sections 9792.20 through 9792.27.23, and it combines clinical treatment guidelines with a drug formulary that physicians and claims administrators must follow when deciding whether a treatment is reasonable and necessary.¹ Recommendations in the MTUS are presumed correct, meaning they apply automatically unless someone successfully challenges them with stronger medical evidence.²

What the MTUS Actually Contains

The treatment guidelines are drawn mainly from the American College of Occupational and Environmental Medicine (ACOEM). ACOEM covers common occupational problems including low back disorders, initial treatment approaches, work disability prevention, and cannabis-related workplace issues. Where ACOEM is silent or incomplete, the Official Disability Guidelines (ODG) fill in as a supplementary source.¹

The whole structure rests on evidence-based medicine. The regulation says plainly that unsystematic clinical experience and reasoning from first principles alone are not enough to justify a treatment decision; the best available scientific data has to drive the choice.²

When Your Condition Isn’t in the Guidelines

Care cannot be refused just because the MTUS doesn’t mention your particular condition. When the adopted guidelines are silent, the physician or reviewer has to work through a prescribed search sequence to find the best available evidence:

Check the current MTUS guidelines (ACOEM and ODG) for an applicable recommendation.
If nothing applies, search the most current versions of ACOEM or ODG for a recommendation outside what the MTUS has formally adopted, using whichever is backed by the stronger evidence.
If still nothing applies, search other nationally recognized, evidence-based medical treatment guidelines.
If no guideline covers the condition, look to current peer-reviewed studies in nationally recognized medical journals.

At every step, the quality and strength of the evidence has to be evaluated using the methodology set out in Section 9792.25.1.³

The Drug Formulary

The MTUS Drug Formulary sorts medications into three categories that control how easily they can be prescribed for a work injury:

Exempt drugs can be prescribed or dispensed without prior authorization from the claims administrator, as long as the prescription is consistent with the MTUS guidelines. For physician-dispensed exempt drugs, there is a cap of one seven-day supply at the initial visit within seven days of the injury date. A brand-name version prescribed when a generic equivalent exists still requires prior authorization.
Non-exempt drugs require authorization through prospective review before the physician can prescribe or dispense them.
Unlisted drugs, meaning anything not appearing on the formulary list, are handled the same as non-exempt medications and require prospective review before dispensing.

The Division of Workers’ Compensation updates the formulary periodically to reflect new clinical data and FDA approvals.⁴ Common, well-established drugs for acute injuries can reach the patient quickly, while medications with higher risk profiles or costs receive closer scrutiny.

How Treatment Requests Get Reviewed

For any non-exempt treatment or medication, the treating physician has to submit a Request for Authorization on the DWC Form RFA. That form is what starts the utilization review process. It can go by fax or through a secure electronic portal, and the transmission has to record the date, time, and destination.⁵

Supporting documentation has to go with the RFA. In practice that usually means the Doctor’s First Report of Occupational Injury or a PR-2 Progress Report describing the patient’s current condition, functional limitations, and response to any prior treatment. If the form is missing the provider’s identity, a description of the requested treatment, supporting documentation, or the physician’s signature, the claims administrator can return it marked “not complete” within five business days.⁵

Claims administrators may also accept requests that don’t use the official DWC Form RFA, provided that “Request for Authorization” is clearly written at the top of the first page, all requested services are listed on that page, and the request includes documentation supporting medical necessity. If expedited review is needed, the physician has to flag that on the RFA at the time of submission.⁵

Decision Timelines

Once the claims administrator receives a completed RFA, the clock starts:

Prospective or concurrent review: the decision to approve, modify, or deny must be issued within five business days of receiving the completed request.
Expedited review: when the injured worker faces an imminent and serious threat to health, or when waiting the standard five days could cause harm, the decision must come within 72 hours. The requesting physician has to certify the urgency in writing and back it with medical evidence. Checking a box isn’t enough; if the evidence doesn’t support urgency, the request reverts to the standard timeline.
Retrospective review: for treatment already provided, the decision must be made within 30 days of receiving the request and sufficient information about the care rendered.

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Every utilization review produces a written decision sent to the injured worker, their attorney if they have one, and the requesting physician. The decision states whether the treatment is approved, modified, or denied. A modification might mean fewer visits than requested or a different medication. Only a licensed physician competent to evaluate the specific clinical issues, and whose scope of practice covers the requested services, can modify or deny a request on medical necessity grounds.⁷

Getting Treatment That Departs from the Guidelines

The presumption of correctness can be overcome, but the physician asking for care outside the MTUS carries the burden. The standard is a preponderance of scientific medical evidence, meaning the physician has to show it is more likely than not that the alternative treatment is reasonably required to cure or relieve the effects of the injury.⁸

This is where the search sequence matters. The physician must identify peer-reviewed studies published in nationally recognized journals or cite other evidence-based guidelines that support the proposed treatment. The studies have to follow rigorous methodologies, and the medical report must explain the specific clinical relevance of each study to the patient’s condition.¹ Vague references to general medical literature won’t work. The evidence has to be identified specifically and tied directly to the case.

Successful rebuttals tend to involve newer research that post-dates the current MTUS adoption, or situations where the patient’s clinical picture is genuinely unusual. Lower-quality evidence like case reports or expert opinion alone rarely succeeds, because the MTUS methodology ranks those at the bottom of the evidence hierarchy.

Appealing a Denial Through Independent Medical Review

When utilization review modifies or denies a treatment, the injured worker or their representative can request an Independent Medical Review. IMR is the primary appeals mechanism in California workers’ compensation for disputes about medical necessity. The request has to be filed within 30 days of receiving the utilization review determination, using the IMR application form that comes with the UR decision from the claims administrator.⁹

The DWC contracts with an independent medical review organization (currently Maximus) to run these reviews. Within one business day of determining the dispute is eligible, Maximus sends a Notice of Assignment indicating whether the review will be regular or expedited.⁹

The IMR decision binds all parties and is treated as the determination of the Administrative Director. The Workers’ Compensation Appeals Board cannot substitute its own finding of medical necessity for a final IMR determination. There is no filing fee for the injured worker.¹⁰

Challenging an IMR Decision

IMR decisions are final in most cases, but a petition can be filed with the WCAB within 30 days of the determination being mailed. The grounds are narrow and require clear and convincing evidence of one of the following:

The Administrative Director acted beyond their authority.
The determination was obtained through fraud.
The medical reviewer had a material conflict of interest.
The determination resulted from bias based on race, national origin, religion, age, sex, sexual orientation, color, or disability.
The determination was the product of a plainly erroneous mistake of fact.

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The petition must spell out the factual and legal grounds in full detail, and any objection not raised is permanently waived. It has to include a copy of the IMR determination, proof of service, and the assigned case numbers. If the WCAB reverses the determination, the dispute goes back to the Administrative Director for assignment to a different review organization, or, if none is available, a different individual reviewer.¹¹

The clear and convincing evidence standard is deliberately high. Disagreeing with the medical conclusion is not enough on its own. Successful appeals usually involve procedural defects or demonstrable conflicts of interest rather than second-guessing the reviewer’s clinical judgment.

1
California Department of Industrial Relations. DWC Medical Treatment Utilization Schedule
2
Department of Industrial Relations. California Code of Regulations Title 8 Section 9792.21 – Medical Treatment Utilization Schedule
3
Department of Industrial Relations. California Code of Regulations Title 8 Section 9792.21.1 – Medical Evidence Search Sequence
4
California Department of Industrial Relations. MTUS Drug List V14 Addendum Two
5
Cornell Law School Legal Information Institute. California Code of Regulations Title 8 Section 9792.9.1 – Utilization Review Standards
6
Department of Industrial Relations. California Code of Regulations Title 8 Section 9792.9.3 – Utilization Review Timeframes
7
Cornell Law School Legal Information Institute. California Code of Regulations Title 8 Section 9792.7 – Utilization Review Standards
8
Cornell Law School Legal Information Institute. California Code of Regulations Title 8 Section 9792.21 – Medical Treatment Utilization Schedule
9
California Department of Industrial Relations. DWC Independent Medical Review (IMR)
10
California Department of Industrial Relations. DWC Independent Medical Review (IMR) FAQs
11
Cornell Law School Legal Information Institute. California Code of Regulations Title 8 Section 10575 – Petition Appealing Independent Medical Review Determination