My 35 year old husband recently had a four-hour glucose tolerance test to look for hypoglycemia. The test concluded that he did not have hypoglycemia, yet he has all the symptoms, and has had them since childhood. We recently were able to test his glucose level at home during an episode and it was 54 mg/dl [3 mmol/L]. After 30 minutes, it was up to 75 mg/dl [4.2 mmol/L]. On another day (without symptoms) it was 127 mg/dl [7.1 mmol/L] There are several people in his family with hypoglycemia or diabetes. Is there another type of test we should request?

The oral glucose tolerance test for hypoglycemia is overused, and is not helpful. An abnormal response is neither necessary or sufficient to make the diagnosis of reactive hypoglycemia.. Reactive hypoglycemia is similar to an inability to brake the secretion of insulin after a meal challenge. Rather than stopping the insulin secretion before hypoglycemia begins, it is stopped after symptoms have already begun. This should be distinguished from fasting hypoglycemia which could be from a tumor that makes insulin. The usual treatment for reactive hypoglycemia is supportive. It relies on using small, frequent feedings throughout the day with an avoidance of problem foods known to worsen the symptoms. Fortunately, the problem seems to get better on its own over time.

JTL