What Is a Normal Fasting Blood Sugar Level?

A fasting blood sugar test measures glucose after 8+ hours without food. It is the standard screening test for diabetes.

Reference Ranges (Fasting)

• Normal: 70–99 mg/dL
• Prediabetes: 100–125 mg/dL
• Diabetes: 126 mg/dL+ (two tests)
• Hypoglycemia: below 70

How to Prepare

• No food or caloric drinks for 8+ hours
• Water is fine
• Take medications as usual unless told otherwise
• Best drawn in the morning

What Affects Results

• Recent food intake (elevates)
• Stress or illness (elevates)
• Certain medications (steroids elevate)
• Alcohol the night before (can lower)