Blood glucose is a term that describes your body's circulating levels of glucose, an energy source derived from foods that contain carbohydrates. Under normal circumstances, your body tries to keep your blood glucose within a relatively narrow range. Glucose levels that fall consistently above or below this range can lead to a number of serious health problems.
Understanding Blood Glucose
Your body controls your blood glucose levels with insulin and glucagon, two hormones secreted by your pancreas, according to EndocrineWeb. When glucose from food accumulates in your bloodstream, your pancreas releases insulin, which chemically signals the cells in your body to give glucose entry into their interiors. Insulin also promotes the storage of excess glucose in your liver. When your blood glucose levels fall too low, insulin production drops and your pancreas releases glucagon, which chemically signals your liver to release its stored glucose content back into your bloodstream. The overall effect of this activity is maintenance of your blood glucose within a range that supports your health and energy needs.
Testing Procedures
Your doctor can test your blood glucose levels with either of two standard testing procedures, EndocrineWeb reports. In a fasting blood glucose test, he will measure your glucose with a blood test performed after you have gone without food overnight. In an oral glucose tolerance test, you will first undergo a blood test after fasting for a period of 10 to 16 hours. Next, you will drink a solution that contains a high amount of sugar. You will then undergo additional blood tests at intervals of 30 minutes, 1 hour, 2 hours and 3 hours.
Normal Results
During a fasting blood glucose test, normal values for blood glucose range between 70 and 110 mg/dL of blood, EndocrineWeb reports. If you undergo a glucose test within 2 or 3 hours of a meal, your glucose may safely range as high as 180 mg/dL. If you undergo an oral glucose tolerance test, your blood glucose should normally fall below 200 mg/dL. Blood glucose readings below 70 mg/dL indicate the presence of low blood sugar, or hypoglycemia. Readings above 180 mg/dL indicate the presence of high blood sugar, or hyperglycemia. If two or more of your readings on an oral glucose test exceed 200 mg/dL, you have diabetes.
Hyperglycemia and Hypoglycemia
You may develop hyperglycemia for reasons unrelated to diabetes, according to MedlinePlus. Additional potential causes include high thyroid output, pancreatitis, pancreatic cancer and Cushing syndrome. If you develop hypoglycemia, potential underlying causes include low thyroid output, lack of food, low pituitary output and excessive amounts of glucose medications, such as insulin. You may also experience temporary blood glucose elevations as a result of stress. A wide range of medications may temporarily raise or lower your blood glucose.
Diabetes
If you have diabetes, you should check your blood glucose regularly, the American Diabetes Association reports. This is especially true if you are pregnant, take insulin or other diabetes medications, have difficulty controlling your glucose levels or have severely low blood glucose.
