What is a fasting blood sugar test and what do the numbers mean?

A fasting blood sugar test measures the amount of glucose in your blood after you haven't eaten or drank anything (except water) for at least 8 to 10 hours. It is usually done first thing in the morning. Fasting provides a baseline metric, showing how your body manages blood sugar without the immediate influence of food. A normal fasting blood sugar level is less than 100 mg/dL. A level between 100 and 125 mg/dL indicates prediabetes, and 126 mg/dL or higher on two separate tests confirms a diagnosis of diabetes.