The results of a hemoglobin A1c test helps doctors determine if a diabetic is managing his diabetes appropriately, notes WebMD. A1c measures the amount of hemoglobin on the red blood cells, which is an indicator of the average blood sugar for recent weeks. A1c tests allow doctors to determine if the current treatment plan is effective or if changes must be made.
The normal A1c range is 4 to 5.6 percent, notes WebMD. A level of 5.7 to 6.4 percent is cause for alarm because it indicates an increased risk for the person developing diabetes. A reading of 6.5 percent or more indicates that the person has diabetes.