Doctors often check fasting blood sugar levels to see if you have diabetes. Fasting blood sugar or glucose levels are done after you've fasted for between 8 and 12 hours, depending on your doctor's instructions. People who have diabetes have higher fasting blood sugars, sometimes abbreviated as FBS than people who do not have diabetes. People with prediabetes have FBS levels higher than normal but not as high as people with diabetes.
Normal Levels
The normal fasting glucose level is between 70 and 100 mg/dL. If your level is below 70 mg/dL you may be diagnosed with hypoglycemia, blood sugar levels that are too low. Hypolgycemia can cause symptoms such as weakness, dizziness, trouble concentrating, shakiness, hunger, sweating or even fainting.
Prediabetic Levels
Fasting blood glucose levels between 100 and 125 mg/dL are considered to be prediabetic levels. As many as 57 million American have prediabetes, according to the American Diabetic Association. If you fall into this category, you're almost certain to develop diabetes within the next 10 years, unless you lose as little as 5 to 7 percent of your body weight, the National Institute of Diabetes and Digestive and Kidney Disorders warns. Your doctor may suggest lifestyle modifications such as losing weight, quitting smoking and exercising as ways to bring your glucose levels down into the normal range.
High Levels
If your fasting blood glucose readings rise above 126 mg/dL on two separate occasions, you may be diagnosed with diabetes, unless you have other health conditions or are taking medications that might cause a temporary rise in glucose levels. Conditions that could raise your glucose levels include extreme physical stress from acute injuries such as severe burns, heart attack or stroke. Taking medications such as steroids can also raise your fasting glucose levels temporarily. In the United States, over 90 percent of all people with diabetes have type 2 diabetes, previously called adult-onset diabetes. Over 50 percent of people with type 3 diabetes don't realize they have it, New-York Presbyterian Hospital reports.
Normal Levels for Diabetics
It's often difficult for diabetics to keep their blood glucose levels in the normal range, and in some cases, your doctor may not want you to lower your blood sugar levels to normal levels, because of the risk of hypoglycemia. Your doctor will tell you what he considers a good range for your blood sugar if you're already diabetic, which may be higher than the range considered normal for people without diabetes. For people with diabetes, glucose levels between 70 and 130 mg/dL might be considered normal, according to the Joslin Diabetes Center of Harvard Medical Center.
References
- Joslin Diabetes Center: Goals for Blood Glucose Control
- University of Washington;Understanding Diabetes; Barak Gaster, M.D.
- National Institute of Diabetes and Digestive and Kidney Disorders; nsulin Resistance and Pre-diabetes; October 2008
- New York-Presbyterian Hospital; Diabetes, Type 2; November 2008
