What range defines impaired fasting glucose?

• A. 100-125 mg/dL
• B. 126-139 mg/dL
• C. 90-99 mg/dL
• D. 140-199 mg/dL

Answer: (A)

Impaired fasting glucose is defined by a fasting plasma glucose level between 100 and 125 mg/dL after at least 8 hours without food. This range marks higher-than-normal fasting glucose but stops short of diabetes, which is diagnosed when fasting glucose reaches 126 mg/dL or higher on separate occasions. Values below 100 mg/dL are considered normal, and 126 mg/dL or higher on a fasting test is diabetes (usually confirmed with a repeat test). The 140–199 mg/dL range is associated with the 2-hour glucose value after an oral glucose tolerance test (impaired glucose tolerance), not fasting. So the 100–125 mg/dL range best defines impaired fasting glucose.