In healthy adults, the typical fasting blood glucose range is:

• A. 60-80 mg/dL
• B. 80-120 mg/dL
• C. 100-140 mg/dL
• D. 120-160 mg/dL

Answer: (B)

Fasting blood glucose measures the baseline glucose level after an overnight fast, when the body is not recently influenced by a meal. In healthy adults, insulin regulation keeps this fasting value within a narrow range, typically about 80 to 120 mg/dL, with most people around 90 mg/dL. Values well below this range can signal hypoglycemia, while consistently higher values point to impaired glucose regulation or diabetes. For reference, fasting glucose of 100–125 mg/dL on repeat testing is considered impaired fasting glucose (prediabetes), and 126 mg/dL or higher on two occasions indicates diabetes. Among the options, 80–120 mg/dL best represents the normal fasting range. The other ranges are either too low or extend into levels associated with impaired glucose tolerance or diabetes.