Maximum Medical Improvement (MMI)

In workers’ compensation, an authorized treating physician (ATP) is responsible for determining when
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In workers’ compensation, an authorized treating physician (ATP) is responsible for determining when an injured worker (IW) has reached maximum medical improvement (MMI) from the effects of the industrial injury.

MMI is the point in time when:

  • The underlying condition causing the disability has become stable, and;
  • No further treatment is reasonably expected to improve the condition.


The type of claim determines the time for submitting the report and what needs to be included in the report. Although the maximum time to return reports is listed below, rapid submission of the report will avoid further delay of the IW resuming work.

  • Medical only (no lost time) claims: The WC164 form must be received within seven calendar days from the date of MMI.
  • Indemnity (lost time) claims with no impairment: The WC164 form and office notes must be received within seven calendar days from the date of MMI.
  • Indemnity (lost time) claims with impairment: The WC164 form, the impairment rating sheets, and office notes must be received within 14 calendar days from the date of MMI.

If a full duty release is prior to the determination of MMI, inform the employer and send records to Pinnacol as quickly as possible.

If the IW is unable to come back to full duty, the MMI report should clearly state the permanent restrictions.

Impairment ratings

When the ATP has determined the IW is at MMI and has not returned to his/her pre-injury state, physically and/or mentally, the ATP determines or causes to be determined a permanent medical impairment rating. If there is impairment as a result of the industrial injury, a Colorado Level II accredited provider must perform the impairment rating. The IW’s level of permanent medical impairment must be determined in accordance with the Revised Third Edition of the AMA Guides.

Independent medical exams

Pinnacol may request an independent medical exam (IME) to determine if MMI has been reached. Although Pinnacol cannot direct medical care, Pinnacol can ask what additional treatment will improve the IW’s condition, and may question whether functional gain has been achieved after a course of treatment.

Maintenance care following MMI

IWs may require treatment after MMI to maintain their functional status. The ATP should indicate whether continuing care is needed in the “maintenance care after MMI” section on the WC164 form. The follow-up care must be documented in the final report.

Provider assessment of need for treatment after MMI

If an IW goes back for additional non-maintenance care after MMI has been declared, a medical narrative report should be submitted to Pinnacol. If there is a lapse in treatment of more than 60 days on a non-lost-time claim, a narrative report should be submitted.

The following questions should be addressed in the narrative:

  1. When was the IW last seen?
  2. What was the date of MMI from the original injury?
  3. What are the IW’s current symptoms or complaints?
  4. Has there been a new occupational injury or disease? If yes, please explain.
  5. Is it medically probable that the IW’s current condition was caused by a new occupational injury or exposure or related to the original compensable injury?
  6. Has there been a condition change that necessitates rescinding MMI from the original injury to provide further treatment?

If additional treatment is needed, a detailed treatment plan, including the type of treatment needed, the duration of that treatment, and work restrictions, should be submitted to Pinnacol. The anticipated new date of MMI should also be stated on the treatment plan.

MMI Challenges

The impairment rating and/or the date of MMI can be challenged by requesting a Division Independent Medical Exam (DIME) from the Division of Workers’ Compensation.

Injured workers who fail to go back for treatment

When an ATP recommends a another visit and the IW does not go back after two or more scheduled appointments, the ATP is not abandoning the IW. The IW may voluntarily terminate the relationship by ignoring the advice to receive further treatment and choosing not to go back. The IW’s failure to go back effectively terminates the physician-IW relationship and the ATP may consider this to be noncompliance on the part of the IW.

The ATP need not formally notify the IW or the insurer under this circumstance unless the ATP independently decides to discharge the IW for nonmedical reasons. The ATP must exercise independent judgment on whether and when to discharge an IW.

If the ATP decides to discharge an IW, Pinnacol or the employer will send the IW a letter asking whether the IW requires additional medical treatment or is claiming permanent impairment. The letter is sent after the second missed medical appointment and asks the IW to respond within 30 days.

Questions? Please contact us at or 303.361.4945.

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