A blood glucose test measures the amount of a sugar called glucose in a sample of your blood.
Glucose is a major source of energy for most cells of the body, including those in the brain. Carbohydrates (or carbs) are found in fruit, cereal, bread, pasta, and rice. They are quickly turned into glucose in your body. This raises your blood glucose level.
Hormones made in the body called insulin and glucagon help control blood glucose levels.