The Global Assessment of Functioning (GAF) scale is found in the DSM-IV-TR, but was eliminated from the largely discredited and ignored DSM-5. When assigning a GAF score the doctor is required by DSM-IV-TR protocol to provide both the current GAF score and the highest GAF score the patient achieved in the previous 12 months. If the doctor has not done so they have left out some important and required information about the patient.
Check out my blog (http://drleckart.blogspot.com). More help can be found at my website (www.drleckartwetc.com) and in my book Psychological Evaluations In Litigation: A Practical Guide for Attorneys and Insurance Adjusters