Your body converts sugar, or glucose, into energy so your body can function. This glucose comes from the foods you eat and is released from storage from your body’s own tissues.
Insulin is a hormone made by the pancreas. Its job is to move glucose from the bloodstream into the cells of tissues. After you eat, the level of glucose in the blood rises sharply. The pancreas responds by releasing enough insulin to handle the increased level of glucose — moving the glucose out of the blood and into cells. This helps return the blood glucose level to its former, lower level.
If a person has diabetes, two situations may cause the blood sugar to increase: the pancreas does not make enough insulin or the insulin is not received by the cells. As a result of either of these situations, the blood sugar level remains high, a condition called hyperglycemia or diabetes mellitus. If left undiagnosed and untreated, the eyes, kidneys, nerves, heart, blood vessels and other organs can be damaged.
Conversely, the opposite can happen too. Too low a level of blood sugar, a condition called hypoglycemia, can be caused by the presence of too much insulin, other hormone disorders or liver disease.
This test can be used for the diagnosis of diabetes mellitus; evaluation of carbohydrate metabolism disorders, including alcoholism; evaluation of acidosis and ketoacidosis; evaluation of dehydration, hypoglycemia of insulinoma, and neuroglycopenia.