Independent Medical Review (IMR)

What is IMR

California's workers' compensation system uses a process called independent medical review (IMR) to resolve disputes about the medical treatment of injured employees. As of July 1, 2013, medical treatment disputes for all dates of injury will be resolved by physicians through an efficient process known as IMR, rather than through the often cumbersome and costly court system.

A request for medical treatment in the workers' compensations system must go through a "utilization review" process to confirm that it is medically necessary before it is approved. If utilization review denies, delays or modifies a treating physician's request for medical treatment because the treatment is not medically necessary, the injured employee can ask for a review of that decision through IMR.

The costs of IMR are paid by employers who are required by law to provide injured employees with all medical treatment that is reasonable and necessary to cure or relieve the effects of a work-related injury. The DWC is required to contract with one or more independent medical review organizations (IMROs) to conduct IMR on its behalf.

The costs of IMR are based upon the nature of the medical treatment dispute and the number of medical professionals needed to resolve the dispute, and are significantly lower than the cost to resolve a dispute through litigation.

For IMR requests submitted on or after Jan. 1, 2020:

  • Standard IMRs involving pharmacy and non-pharmacy claims: $345 per IMR.
  • Expedited IMRs involving pharmacy and non-pharmacy claims: $345 per IMR.
  • IMRs terminated or dismissed before forwarding to a medical professional reviewer: $115 per IMR.
  • IMRs terminated or dismissed after forwarding to a medical professional reviewer: $345 per IMR.

IMR Decisions Search Tool

IMR decisions are posted on DWC’s website after being issued. IMR cases withdrawn or determined to be ineligible are not posted. The DWC IMR search tool allows users to easily research the database of IMR case decisions.

Keys to a successful IMR

It is the claims administrator's responsibility to:

  • Send the injured worker a copy of the utilization review (UR) decision letter on a request for treatment, and, if applicable, the supporting recommendation by a utilization review organization
  • Send the completed IMR application form (DWC IMR-1 form) to the injured worker if the UR decision delays, denies or modifies the request for treatment
  • Make sure the IMR application form is the correct DWC IMR-1 form (not MPN-IMR form, not a modified or self-created form)
  • Clearly indicate type of review on the application, either expedited (EXP) or regular (REG). Expedited reviews must be accompanied by a physician statement of necessity or the UR must have been conducted in an expedited manner
  • Include the WCIS number (also known as the JCN)
  • Indicate whether liability is being disputed on the application. If liability is disputed, IMR is not available until the liability issue has been resolved. For claims that are under investigation and for which liability has not yet been denied, IMR is available within the first 90 days after the claim is presented, for medical treatment costs up to $10,000.

If you are an injured worker or the designee, to submit a request for IMR, it is very important do the following:

  • Include a copy of the complete utilization review (UR) determination with the IMR application form that was provided to you by your claims adjustor
  • Sign the IMR application form before submitting a request for IMR
  • Send the signed IMR application and the UR determination within 30 days of receiving the UR determination to the address on the form.

As of July 1, 2013, all dates of injury are eligible for IMR.

Mail the above information to:

c/o Maximus Federal Services, Inc.
PO Box 138009
Sacramento, CA 95813-8009

If you did not receive or have misplaced the IMR application form, you may contact the claims administrator for another copy.

For questions regarding your IMR request, please contact your employer's insurance company claims administrator.

What happens after the Administrative Director determines the dispute is eligible for IMR?

  • Within one business day of the Administrative Director's finding that a dispute is eligible for IMR, Maximus will send the parties a Notice of Assignment and Request for Information (NOARFI), which informs the parties that the dispute has been assigned for review and whether the review will be “regular” or “expedited.”
  • For a regular review:
    • The required medical records must be provided by the claims administrator to Maximus within 15 calendar days of the date designated on the mailed notification or within 12 calendar days of an electronic notification.
  • For an expedited review:
    • The required medical records must be provided to Maximus within 24 hours following receipt of the notification.
  • The claims administrator must also send the employee or the employee’s representative a notification that lists all of the documents submitted to Maximus and a copy of all of the documents that were not previously provided to the employee or the employee’s representative.
  • The best and most reliable way to transmit medical records to Maximus is via MOVEit.  MOVEit is a web-based portal that allows you to submit files to MAXIMUS securely and electronically. MOVEit provides much better traceability than paper and fax.
  • If you wish to use MOVEit or have questions about it, please feel free to contact MAXIMUS by email at or by phone at 1-855-865-8873.

Contact Maximus

To submit IMR documents via fax:

IMR Application Requests: 916- 605-4270
All other IMR documents (medical records, termination/withdraw requests, etc.): 916- 605-4275

For those interested in becoming an IMR reviewer, please contact Maximus at:

For those interested in becoming an IMR reviewer, please contact Maximus by email at

For additional questions or assistance, please contact Maximus at:

Toll free: 1-855-865-8873
Fax: (916) 605-4270

Contact DWC Medical Unit

For other questions related to the IMR process not addressed above, please contact the DWC Medical Unit:

DWC - Medical Unit
Independent Medical Review
P.O. Box 71010
Oakland, CA 94612

Toll free: 1-800-794-6900
Phone: (510) 286-3700

August 2023