Each letter in the acronym (see box below) is paired with a number from 1 to 4 to designate the service member's physical capacity.
Four numerical designations are used to reflect different levels of functional capacity.
The basic purpose of the physical profile serial is to provide an index to overall functional capacity.
Therefore, the functional capacity of a particular organ or system of the body, rather than the defect per se, is evaluated in determining the numerical designation 1, 2, 3, or 4.
The below definitions are derived from Air Force Instruction 48-123 Medical Examinations and Standards "Table 1.1.