Your blood glucose level can be measured by way of a simple blood test. Since glucose is a type of sugar that is regulated by insulin, blood glucose measurements are usually the first step in diagnosing diabetes. Uncontrolled high blood glucose levels can have long-term health consequences.
Normal Blood Glucose
When you eat a meal, your blood glucose level rises, which signals the pancreas to release insulin. Insulin is stored in the pancreas and helps your body use glucose, ultimately lowering your blood glucose level. Blood glucose levels in patients without diabetes is normally in the range of 100 mg/dL (milligrams per deciliter) under fasting conditions, which refers to not having anything to eat for approximately eight hours prior to having your blood drawn. However, different laboratories will have different normal ranges.
Symptoms and Causes of High Blood Glucose
Symptoms of high blood glucose include increased thirst, increased urination, dry mouth, fatigue, blurred vision or unexplained weight loss. High blood glucose can be a sign of diabetes, a disease where your body either does not produce insulin, known as Type 1 diabetes, or your body does not properly use insulin, known as Type 2 diabetes. People with Type 1 diabetes need to take daily insulin injections. People with Type 2 may require insulin or oral agents to control their blood sugar levels.
Types of Tests
A fasting blood sugar test requires that you do not have anything to eat or drink for at least eight hours prior to the test. A 2-hour postprandial blood sugar test is performed two hours after eating a meal. An oral glucose tolerance test is a series of blood glucose measurements performed after drinking a liquid with known amounts of glucose.
What to Expect on the Day of the Test
Blood glucose levels will be determined by measuring the glucose level in your blood, so a blood sample will need to be drawn from your arm. If you are having a fasting blood glucose level drawn, you will be instructed not to eat or drink for approximately eight hours before the test. A tourniquet will be placed on your upper arm to that the veins in your arms will be visible. The laboratory technician will insert a needle into one of your veins to collect a small sample of blood. You may feel a pinch when the needle is inserted into your arm. The needle is withdrawn after the appropriate amount of blood has been drawn. You may be asked to hold pressure on the puncture site with a gauze pad for several minutes.
Results and Follow Up
Normal blood glucose levels will be in the range of 100 mg/dL under fasting conditions. A 2-hour postprandial level will be in the range of 70 to 145 mg/dL. Random levels will be in the range of 70 to 125 mg/dL. Discuss the results of your blood glucose test with your health care provider. High or low glucose levels can be indicative of a variety of diseases and may require further testing.
