blood glucose level, the concentration of glucose in the blood, represented in milligrams of glucose per deciliter of blood. Normal adult blood glucose levels range from 70 to 115 mg/dL (4 to 6 mmol/L), with generally higher levels after 50 years of age. A fasting serum glucose of 126 mg/dL on two or more occasions signifies diabetes mellitus. A fasting serum glucose of 100 to 125 mg/dL is considered an impaired fasting glucose, a type of prediabetes that increases the risk of developing type 2 diabetes. If a random blood glucose test is done, a level of 200 mg/dL or higher is usually an indicator of diabetes mellitus. See glucose tolerance test. See also hypoglycemia, hyperglycemia, glycosylated hemoglobin.
