If a person with diabetes has severe hypoglycemia, he or she may not be able to answer the doctor's questions because of confusion or unconsciousness. In this case, a family member or close friend will need to describe the patient's medical history and insulin regimen. To help ensure effective emergency treatment, all people with diabetes should consider wearing a medical alert bracelet or necklace. This potentially lifesaving jewelry will identify the patient as having diabetes, even if the patient is far from home and traveling alone. Family members or friends of a person with diabetes should learn how to bring a patient out of severe hypoglycemia by giving the person orange juice or another carbohydrate, or by giving an injection of the drug glucagon, which can raise blood sugar.
If a person with diabetes can answer questions appropriately, the doctor will ask about his or her current insulin dosage, as well as recent food intake, exercise schedule and other medications. If the patient has been self-monitoring blood sugar with a glucometer (a hand-held device to measure glucose levels in blood from a finger prick), the doctor will review the most recent glucometer readings to confirm low blood sugar and to check for a pattern of hypoglycemia related to diet or exercise.
In people who do not have diabetes, the doctor will review current medications and ask about any history of gastrointestinal surgery (especially involving the stomach), liver disease and an enzyme deficit. Patients should describe their symptoms and when the symptoms occur — whether they occur before or after meals, during sleeping or after exercise.
In a person with diabetes, the diagnosis of hypoglycemia is based on symptoms and blood sugar readings. In most cases, no further testing is necessary.
In a person who is not diabetic, the ideal time for diagnostic testing is during an episode of symptoms. At that time, blood can be drawn to measure levels of glucose, and the patient's reactions to glucose intake can be tested. If these measures confirm the diagnosis of hypoglycemia, blood can be sent to a laboratory to measure insulin levels. If the patient has no symptoms at the time of evaluation, the doctor may ask him or her to measure his or her blood glucose when hypoglycemic symptoms occur. In non-diabetics, a blood sample can be tested to measure liver function and cortisol levels. If an insulinoma is suspected, the doctor may order a supervised 48-hour fast. During that period, blood levels of glucose and insulin will be measured whenever symptoms occur or once every six hours, whichever comes first. A blood glucose level of less than 40 milligrams per deciliter with a high level of insulin strongly suggests the person has an insulinoma or has given himself or herself an insulin injection.
If a person develops symptoms of hypoglycemia only after eating, the doctor may ask him or her to self-monitor blood sugar with a glucometer at the time the symptoms occur.