Permanent partial disability is any anatomic or functional abnormality or loss after maximum medical improvement (MMI) has been achieved. At MMI, the worker's condition is determined to be stable or nonprogressive at the time the evaluation is made. A permanent partial disability award is a monetary award designed to compensate the worker for the amputation or loss of function of a body part or organ system. Impairment is evaluated without reference to the nature of the injury or the treatment given. To ensure uniformity, consistency and fairness in rating permanent partial disability, it is essential that injured workers with comparable anatomic abnormalities and functional loss receive comparable disability awards. As such, the amount of the permanent partial disability award is not dependent upon or influenced by the economic impact of the occupational injury or disease on an individual worker. Rather, Washington's Industrial Insurance Act requires that permanent partial disability be established primarily by objective physical or clinical findings establishing a loss of function. Mental health impairments are evaluated under WAC 296-20-330 and 296-20-340.