Glucose is the simple sugar in your blood that provides your body with energy. In healthy individuals, the body is able to keep blood glucose levels within healthy ranges with the help of the hormone insulin. The American Diabetes Association recommends that overweight or obese adults with one or more risk factors for diabetes have their blood glucose levels checked regularly.
Fasting Blood Glucose
A fasting blood glucose test measures the amount of glucose in your blood after a period of at least eight hours without food or drink. The American Diabetes Association defines normal fasting blood glucose as 70 to 99 mg/dL. If your fasting blood glucose measures between 100 and 125 mg/dL, it is classified as impaired fasting blood glucose, or pre-diabetes. A fasting blood glucose of 126 mg/dL or more on at least two occasions indicates diabetes.
Random Blood Glucose
A random blood glucose test measures your blood sugar level at a random time without any preparation. According to the Virginia Mason Medical Center, a normal random blood glucose level usually falls in the low to mid-100s range. If a random blood glucose test shows that your blood glucose level is 200 mg/dL or higher on more than one testing occasion, a diabetes diagnosis may be made.
Oral Glucose Tolerance Test
An oral glucose tolerance test, or OGTT, measures your body's response to glucose. When you go into your physician's office for an OGTT, your doctor will have you drink a glucose solution that contains 75 g of glucose. Two hours after you consume the glucose solution, your blood glucose level is measured. A healthy glucose level falls below 140 mg/dL. If your glucose level falls between 140 and 200 mg/dL two hours after the glucose solution, it is classified as impaired glucose tolerance or pre-diabetes. An OGTT result of over 200 mg/dL on more than one testing occasion indicates diabetes.
Considerations
The National Diabetes Information Clearinghouse notes that if your blood glucose levels are abnormal or indicate pre-diabetes, there are a number of things you can do to decrease your risk of developing diabetes. Losing 5 to 7 percent of your body weight can improve your cells' sensitivity to insulin and help you manage glucose better. Following a low-fat, low-calorie diet and engaging in at least 30 minutes of physical activity on most days of the week can also lower the risk of developing diabetes.
