A1C - test measures your average blood glucose for the past 2 to 3 months. The advantages of being diagnosed this way are that you don't have to fast or drink anything.
Fasting Glucose - If you had a fasting blood glucose test: A level of 100 to 125 mg/dL means you have impaired fasting glucose, a type of prediabetes. This increases your risk of developing type 2 diabetes. A level of 126 mg/dL and higher usually means you have diabetes.