Blood Glucose Test

Your Care Explained > Tests and Procedures : Blood Glucose Test

This blood test, measuring the amount of glucose, is used to screen healthy people for early signs of diabetes during a routine physical exam.

It is advised for pregnant women, people over age 50 and for those at high risk for diabetes. In addition, there is some evidence that a high fasting serum glucose level (110 mg/dL—milligrams per deciliter—and above) signifies a greater risk of heart disease in women than in men. Blood glucose may also be tested in emergencies to determine whether a low or high glucose level is responsible for unconsciousness.

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What To Know If You’re Having a Blood Glucose Test

You shouldn’t eat any food or drink anything other than water within eight hours of your test. If you’re taking any drugs, be sure to let your doctor or the phlebotomist know. Certain medications, such as birth control pills, postmenopausal estrogen therapy, diuretics—even aspirin and Pepto-Bismol—can raise your blood glucose level.

Understanding Your Results

In general, up to 100 mg/dL is considered normal; levels of 100 to 125 mg/dL may indicate insulin resistance or pre-diabetes. Diabetes is typically diagnosed when fasting blood glucose levels are 126 mg/dL or higher.

If your results are above 100 mg/dL, your doctor may want to repeat the test. He or she will discuss steps you can take to lower your glucose levels and whether or not medication is necessary.

Date Last Modified: January 21, 2011

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