What is a normal blood glucose reading?

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Glucose is the primary fuel source used by human and animal cells for their energy. Various medical ailments, such as diabetes, are defined by an unhealthy amount of glucose in the bloodstream.

Virginia Mason Medical Center states that, depending on when the reading is taken, what is considered a normal blood glucose level will vary.


A fasting blood glucose reading is taken after you have gone without food and liquid other than water for at least eight hours. The American Diabetes Association (ADA) states that a normal reading after fasting will range from 70 to 130 mg/dl. Diabetes is usually diagnosed after consecutive readings in excess of 126 mg/dl.

After Eating

When you eat, your body metabolizes your food and releases glucose into the bloodstream. Postprandial tests are performed two hours after eating. The ADA says that normal blood glucose levels will be below 180 mg/dl at this point, but the Diabetes Life website states that it should ideally be below 145 mg/dl.

Random Reading

A random blood glucose test can be taken at any time of day. It is used primarily for a guideline to proper blood sugar control, though a diagnosis of diabetes can be made if this reading is in excess of 200 mg/dl.

Glucose Tolerance Test

An oral glucose tolerance test is a more thorough method of testing how your body responds to glucose. After fasting overnight, you drink sugar water and your blood glucose levels are checked periodically over the next several hours. Readings should be below 140 mg/dl after two hours and should never exceed 200 mg/dl.


Normal blood glucose levels can be maintained through medication and a combination of lifestyle and dietary changes. These changes should be undertaken under a doctor’s supervision.