The sugar in your blood is referred to as glucose. This sugar is the preferred source of energy for your brain and muscles. You obtain glucose from the food you eat, although some glucose is present in your blood even when you do not eat. A doctor can test the amount sugar in your blood and urine and use the results to discover the presence of any underlying medical conditions or abnormalities.
Fasting Glucose
A fasting glucose test is used to measure the amount of glucose in your blood after a period of time without food. Generally, a fasting glucose test is performed after eight hours without food or drink. A normal fasting blood glucose level is less than 100 mg/dL. A fasting glucose level between 100 and 125 mg/dL is considered impaired fasting glucose, which is considered a risk factor for type 2 diabetes. If your fasting glucose exceeds 125 mg/dL, your doctor may diagnose you with diabetes.
Other Causes of High Blood Glucose
While diabetes is the most common cause of high levels of glucose in the blood, other underlying conditions may also lead to impaired glucose control. Other possible causes of high blood glucose levels include an overactive thyroid, pancreatic cancer, inflammation of the pancreas and pancreatic tumors. Cushing syndrome, a disorder characterized by high levels of the hormone cortisol, and acromegaly, a disorder characterized by high levels of growth hormone, are rare causes of increased blood glucose levels.
Low Blood Glucose
Some people may also have decreased levels of glucose in the blood. This condition, called hypoglycemia, can cause increased sweating, heart palpitations, hunger, anxiety and tremors. A severe drop in blood glucose can cause confusion, blurred vision and loss of consciousness. Low blood glucose levels may occur as a result of liver disease, an underactive thyroid, adrenal insufficiency, alcohol abuse and certain medications.
Sugar in Urine
The amount of sugar in your urine is tested with a glucose urine test. Normally, there is no detectable amount of glucose in your urine. If glucose is present, a condition called glucosuria, it may indicate that you have uncontrolled diabetes. If the levels of glucose in your blood get too high, your kidneys pull glucose from the blood and dump it into your urine. Other causes of glucosuria include liver disease, certain medications, hormonal disorders and pregnancy. If a glucose urine test finds that you have glucose in your urine, further testing is necessary to determine the specific cause.
