What is the normal fasting glucose range?

• A. 70-100 mg/dL
• B. 100-140 mg/dL
• C. 40-60 mg/dL
• D. 120-160 mg/dL

Answer: (A)

Fasting glucose reflects the baseline blood sugar after an overnight or prolonged fast. In healthy people, this value stays in a narrow range because the body’s insulin response keeps liver glucose production in check. The normal range is about 70–99 mg/dL, with many sources rounding the upper limit to 100 mg/dL. Values at or above 100 mg/dL but below 126 mg/dL on repeated testing suggest impaired fasting glucose (prediabetes), while 126 mg/dL or higher on two occasions indicates diabetes. Values far outside this window, such as 40–60 mg/dL, indicate hypoglycemia, and 120–160 mg/dL during a fasting test would be considered elevated for fasting and not normal. So the range around 70–100 mg/dL best fits normal fasting glucose.