Glucose Test

November 12, 2012

Glucose Test

A glucose test is used to measure the amount of sugar or glucose in your blood. Sugar levels of up to 100 mg/dL of blood are considered normal. High blood glucose levels may be a sign of diabetes.

Reason for the Test

Your doctor may recommend regular blood sugar testing, especially if you are older than 40 years of age, or have a family history of diabetes. Individuals between 20 and 40 years of age should check their blood glucose levels once a year. You doctor may also recommend glucose test if you are experiencing symptoms such as dizziness, seizures, and changes in mood and behavior.

How to Prepare for the Test?

The standard fasting glucose test measures blood glucose levels after a fasting period of at least eight hours. The random blood glucose test does not require fasting and is a reflection of the amount of glucose you got from your recent meal intake. While the random test does not require any special preparation, you may have to fast for at least 8 to 10 hours before you take the fasting test. Avoid major changes in your eating pattern on the day before the test. You can, however, drink as much water as you want during the fasting period.

The laboratory technician will draw the required amount of blood from your arm for the glucose test. You may feel the prick and some throbbing afterwards. The bleeding should, however, stop within a few minutes.


Blood glucose levels of up to 100 milligrams per deciliter (mg/dL) of blood are considered normal. If your glucose test levels indicate 100 and 125 mg of glucose per dL of blood, you may be in the prediabetic stage. Individuals with diabetes have fasting blood glucose levels that are 126 mg/dL or higher. Your doctor will be able to explain your results further.

Higher-than-normal blood glucose levels may also occur as a result of overactive thyroid gland, pancreatic cancer, pancreatitis and Cushing syndrome. Lower than normal blood sugar levels may occur due to hypopituitarism, hypothyroidism, and reduced food intake.

Risks and Considerations

Glucose test is generally considered safe. Veins and arteries vary in size from one patient to another, and obtaining a blood sample from some people may be more difficult than from others. Some of you may experience excessive bleeding, dizziness, hematoma and infection at the site of sample collection. Severe stress or trauma may alter your blood sugar levels temporarily. Certain medications such as anti-psychotic medications, corticosteroids, oral contraceptives and phenytoin may interfere with the results of your glucose test.

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