Independent Medical Review (IMR)

What IMR is

Independent medical review is how a California injured worker challenges a utilization review decision that denied or modified treatment on medical-necessity grounds. For injuries on or after January 1, 2013, and for UR decisions communicated on or after July 1, 2013, these disputes are resolved only through IMR, not at a hearing (Labor Code section 4610.5). The DWC contracts the reviews out; its IMR page directs filings to Maximus.

The rule and its deadlines

The employee must request IMR no later than 30 days after service of the UR decision, or 10 days for drug formulary disputes (Labor Code section 4610.5(h)). The reviewer decides within 30 days of receiving the request and records for regular reviews, within five working days for formulary disputes, and within three days when the treatment is urgent (Labor Code section 4610.6(d)). An IMR determination can be appealed only by a verified appeal to the WCAB within 30 days of mailing, on narrow grounds proven by clear and convincing evidence (Labor Code section 4610.6(h)).

Why it matters to an applicant firm

The 30-day IMR window is one of the easiest deadlines to miss in a busy WC practice: the UR letter arrives by mail, often to the client, and the clock starts at service. A lapsed IMR request usually means the treatment is gone until a new request for authorization. Firms log every UR denial on arrival and calendar the IMR date that day. The IMR and UR deadlines guide has the full timeline.