What is MMI?

Your patient or injured worker has reached MMI. But what does MMI mean when we’re talking about California workers’ compensation?

MMI is shorthand for Maximum Medical Improvement, defined on pg. 2 of the AMA Guides to the Evaluation of Permanent Impairment 5th Edition as the following:

An impairment is considered permanent when it’s reached Maximal Medical Improvement, meaning it’s well stabilized and unlikely to change substantially in the next year, with or without medical treatment.

The date of MMI is important: it’s the date when a patient is ready for an impairment rating, and for decisions about future care and permanent work restrictions.

How Do You Know if a Patient is MMI?

How can you tell when a work injury has “stabilized” and is “unlikely to change substantially in the next year, with or without medical treatment”?

To find out what goes into determining MMI, keep a few key questions in mind:

1. Is there any on-going medical treatment that will change the injured worker’s functionality?

For instance, imagine a case where a patient has a back injury, and can only lift 25 pounds.

Physical therapy helped improve the patient’s condition in the past, and they still have six more physical therapy visits authorized by the insurance carrier.

In this scenario, the patient may be able to lift more weight after completing all their physical therapy visits.

Why declare a patient MMI if they are in the midst of ongoing treatment that may improve their condition?

2. Is the impairment rating going to change?

Another example: a worker with a shoulder injury is improving their range of motion with physical therapy, but they cannot improve their ability to lift more weight.

Until their range of motion remains the same, they will not be eligible for MMI.

As soon as the claim is filed, MMI becomes the ultimate goal for treatment. Patients obviously want to get bet better after a work injury, but sometimes they continue to have pain. MMI does not mean that the patient is no longer experiencing pain. It’s the doctor’s responsibility to communicate this to the patient, and to everyone involved in the case.

Try RateFast Express today!

AMA Guides 5ed Glossary Definitions (Pages 599-603)

AMA Guides 5ed Glossary Definitions (Pages 599-603)

Below is a common list of terms that help RateFast users better understand the basics definitions used for impairment ratings. You will find many of these terms used in RateFast to provide more consistent and reproducible reports.


A factor(s) (eg, physical, chemical, biological or medical condition) that adversely alters the course or progression of the medical impairment. Worsening of a preexisting medical condition or impairment.


Fixation of a joint in a specific position by disease, injury or surgery. When surgically created, the aim is to fuse the joint in that position, which is best for improved function.


A distribution or allocation of causation among multiple factors that caused or significantly contributed to the injury or disease and existing impairment.

Assistive devices

Devices that help individuals with a functional loss increase function. Examples include reachers, extended grabbers, hearing aids, and telephone amplifiers.


An identifiable factor (eg. accident or exposure to hazards or disease) that results in a medically identifiable condition.

Chronic pain

Pain that extends beyond the expected period of healing or is related to a progressive disease. It is usually elicited by an injury or disease but may be perpetuated by factors that are both pathogenically and physically remote from the original cause. Because the pain persists, it is likely that environmental and psychological factors interact with the tissue damage, contributing to the persistence of pain and illness behavior.

Combined Values Chart

A method used to combine multiple impairments, derived from the formula A+ B(1-A) w combined values of A and B, which ensures that the summary value will not exceed 100% of the whole person.


A permanent shortening (as of muscle, tendon, or scar tissue) producing loss of motion, deformity, or distortion.

Desirable weight

A range of optimal weight given an individual’s sex, age, height and body habitus.


Alteration of an individual’s capacity to meet personal, social, or occupational demands or statutory or regulatory requirements because of an impairment. Disability is a relational outcome, contingent on the environmental conditions in which activities are performed.

Effects of medication

Medication may impact the individual’s sign, symptoms, and ability to function. They physician may choose to increase the impairment estimate by a small percentage (1% to 3%) to account for effects of treatment.

Functional limitations

The inability to completely perform a task due to an impairment. In some instances, functional limitations may be overcome through modifications in the individual’s personal or environmental accommodations.


A historical term used to describe disability or a person living with a disability or disabilities. A handicapped individual has been considered to be someone with a physical or mental disability that substantially limits activity, especially in relation to employment or education.


A loss, loss of use, or derangement of any body part, organ system, or organ function.

Impairment evaluation

A medical evaluation performed by a physician, using a standard method as outlined in the Guides, to determine permanent impairment associated with a medical condition.

Impairment percentages or ratings

Consensus derived estimates that reflect the severity of the impairment and the degree to which the impairment decreases an individual’s ability to perform common activities of daily living as listed in Table 1-2.


A conscious and willful feigning or exaggeration of a disease or effect of an injury in order to obtain specific external gain. It is usually motivated by external incentives, such as receiving financial compensation, obtaining drugs, or avoiding work or other responsibilities.

Maximum medical improvement (MMI)

A condition or state that is well stabilized and unlikely to change substantially in the next year, with or without medical treatment. Over time, there may be some change, however, further recovery or deterioration is not anticipated.


A range or zone that represents healthy functioning and varies with age, gender, and other factors, such as environmental conditions.


An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.


A sensation of prickling, tingling, or creeping on the skin, usually associated with injury or irritation of a sensory nerve or nerve root.

Permanent impairment

An impairment that has reached maximal medical improvement.


An artificial device to replace a missing part of the body.


Any pathological condition of the nerve roots.


A return of the disorder or disease after a remission.


Synonymous with reliability. Consistency in results when examinations (tests) are repeated.


Pain along the course of a sciatic verve, especially in the back of the thigh, caused by compression, inflammation, or reflex mechanisms.


A radiographic method used to determine actual limb length.


The action or manner of treating an individual, medically or surgically. Medical treatment is the action or manner of treating an individual, medically or surgically by a physician. Treatment may include modalities recommended by a health care provider.


An accurate measurement apart from random errors. Validity refers to the extent to which a test measures what it is intended to measure.

Whole person impairment

Percentages that estimate the impact of the impairment on the individual’s overall ability to perform activities of daily living, excluding work.

Workers’ compensation

A compensation program designed to provide medical and economic support to workers who have been injured or become ill from an incident arising out of and in the course of their employment.

Try RateFast Express today!

Increase Your Impairment Rating Accuracy

Understanding impairment is essential to workers’ compensation cases. Without a working definition of how the AMA Guides approaches impairment, accurate impairment ratings are impossible to assign or review. If you are working in the world of California workers’ compensation then you understand how complex impairment rating can be.

If you don’t have a thorough knowledge of how ratings are assigned in accordance with the AMA Guides then the accuracy of your permanent and stationary reports may be suffering. This leads to delays in patient care as well as extra work for you and your staff. 

Impairment severity, functional limitations and regional impairments… there’s a lot to wade through. Fortunately there’s a simple explanation for all of these moving parts. To learn more about the whole body approach to impairment simply follow RateFast’s easy walkthrough. How does the AMA guides fifth edition approach impairment? There are only 6 facts to keep in mind:

  1. The impairment severity reflects resulting in functional limitations.
  2. Most chapters report impairment as a whole person impairment units.
  3. Upper and lower extremity chapters have a regional impairments to assign additional weighted value to the specific areas of the arms and legs.
  4. Chapter 16, the upper extremities report sub impairment at the levels of digits, hand, and upper extremity.
  5. Chapter 17 the lower extremities report sub impairment at the levels of foot and lower extremity.
  6. Regional impairments of the spine are weighted accordingly to contribution of function.

So let’s say there’s a 52-year-old right-hand dominant labor worker sustained an amputation to his right thumb at the MP joint (40% HI), and the right small finger at the MP joint (10% HI).

Why is there such a big difference in impairment values? Using the organ system and whole body approach to impairment, the thumb is given four times the value as the little finger for functionality importance. Remember, The Guides 5th edition gives relative weights to organs and body systems. A keen understanding is critical to creating and reviewing accurate and reproducible impairment reports

Try RateFast Express today!

What are Activities of Daily Living in the AMA Guides 5th Edition?

An impairment report without an inventory of the patient’s Activities of Daily Living (or ADLs, as we like to say) is like trying to drive to an unknown destination without a map. After all, how can you determine the severity of an injured worker’s impairment without understanding how his or her daily life is (or isn’t) affected?

If you’re a provider writing an impairment report such as a PR-4 report, then asking your patient about his or her activities of daily living is essential. If you’re a claims adjuster or an attorney reviewing an impairment report, keep an eye out for whether or not the physician has made note of the ADLs.

What You Should Know About Activities of Daily Living

  • In the the AMA Guides 5th Edition, the Activities of Daily Living (ADLs) are an inventory of 34 activity measurements that show how an injury affects the life of the individual (page 4).
  • The activities of daily living include basic functions such as eating, speaking, personal hygiene, and moving around.
  •  The doctor’s description of ADLs serves as objective support when adjusting the final injury value (Whole Person Impairment WPI) up or down.
  • Once determined, the ADL value may serve this function for multiple impairments being calculated. For example, a shoulder injury may not even consider ADL, while a skin injury requires the ADLs to place the condition in a primary category. Other conditions use ADLs somewhere in between, such as determining the influence of pain on a nerve function.

Attention Medical Providers!

If you are examining a worker who has injured multiple body parts, then a separate ADL inventory must be performed on each injured body part. For example, if the worker has injured both her knee and her shoulder, then you should check to see how both her shoulder injury and her knee injury affect each activity.

It’s a lot of work, but it’s necessary. Here’s why:

  1. A complete ADL inventory tells the person who reads the report (such as an insurance administrator) that you invested additional time and effort into understanding the employee’s level of disability.
  2. A complete survey of the activities of daily living is a set of data that further supports the conclusions and final calculations of the reports impairment rating.

For example…

If you, as a medical provider, assign a worker’s injury a very high impairment rating—such as 90% whole person impairment—then the claims adjuster for the claim needs to understand why. If you demonstrate that the injury has disrupted all of the worker’s activities of daily living, then the impairment rating is supported. But if you don’t mention the activities of daily living at all, then you might very well receive a phone call from the insurance company in short order.

Reports that lack mention of the complete ADL inventory should be carefully considered before the conclusions are accepted as valid.

If a reader of an impairment report is unable to understand how much an injury affects the individual’s daily life, understanding the reasons for arriving at the final whole person impairment (WPI) are nearly impossible.

Bottom line: If you create impairment reports, include a complete ADL inventory. If you’re a RateFast user, then you already know that our PR-4 report-writing system  ensures that you ask about each activity for all body parts.

If you review impairment reports, insist that activities of daily living inventories are provided.

Try RateFast Express today!


How to Calculate an Impairment Rating for a Skin Condition

Does Impairment Rating Get Under Your Skin?

Today we Chapter 8 in the AMA Guides 5th Edition: “The Skin.” Specifically, we want to make sure that you place a skin condition in the appropriate class for impairment rating.

The rating table, found on page 178 of the Guides, represents the rating strategy for the entire “Skin” chapter. The rating method is a class based rating system comprised of 5 classes. The whole person impairment range for the chapter is 0-95%.

The rating method in this chapter is primarily driven by the impact of the skin condition on activities of daily living (ADL;Table 1-2 Page 4).

Inventory the Activities of Daily Living!

Initial classification of the skin condition is based on determining how many ADLs (activities of daily living) are “limited.” The ADLs that are considered to be limited by the industrial injury or condition are then grouped into the following categories:

  1. No (none)
  2. Few
  3. Many
  4. Most

Classes 3 and 4 are differentiated by “intermittent confinement at home or domicile.”


When creating or reviewing an impairment rating for the injured employee’s skin, make certain the ADLs have been properly reviewed. It is necessary that those ADLs used to classify the rating category clearly are indicated as “limited.” When “Many” ADLs are reported as “limited,” a statement should be included if the condition results in the individual being confined to his or her home.

Try RateFast Express today!

What exams are included in the RateFast application?

In order to guarantee accurate impairment ratings and truly complete work-comp reports, the Ratefast app guides users through various medical examinations according to the requirements of the AMA Guides.

RateFast asks questions, prompts you to indicate abnormalities, and requests that you take measurements based on your patient’s injury. A set of these questions and prompts for measurements are called exams.


RateFast currently has customized exams for injuries to the following body parts:

  • AMA Guides 5th edition cervical spine exam
  • AMA Guides 5th edition thoracic spine exam
  • AMA Guides 5th edition lumbar spine exam
  • AMA Guides 5th edition shoulder exam
  • AMA Guides 5th edition elbow exam
  • AMA Guides 5th edition wrist exam
  • AMA Guides 5th edition thumb exam
  • AMA Guides 5th edition index finger exam
  • AMA Guides 5th edition middle finger exam
  • AMA Guides 5th edition ring finger exam
  • AMA Guides 5th edition little finger exam
  • AMA Guides 5th edition pelvis/hip exam
  • AMA Guides 5th edition shoulder exam
  • AMA Guides 5th edition knee exam
  • AMA Guides 5th edition ankle/foot exam
  • AMA Guides 5th edition toe exam
  • AMA Guides 5th edition skin exam (for various skin areas)

Related Reading

If you’re a current RateFast user and you want to learn how to access the body part exams, then check out this article in the How to Use RateFast – Basic Tasks section.

Try RateFast Express today!