The NIDDK on Hypoglycemia
To diagnose hypoglycemia in people who do not have diabetes, the doctor looks for the following three conditions:
The patient complains of symptoms of hypoglycemia
Blood glucose levels are measured while the person is experiencing those symptoms and found to be 45 mg/dL or less in a woman or 55 mg/dL or less in a man
The symptoms are promptly relieved upon ingestion of sugar
For many years, the oral glucose tolerance test (OGTT) was used to diagnose hypoglycemia. Experts now realize that the OGTT can actually trigger hypoglycemic symptoms in people with no signs of the disorder. For a more accurate diagnosis, experts now recommend that blood sugar be tested at the same time a person is experiencing hypoglycemic symptoms.
The doctor will also check the patient for health conditions such as diabetes, obtain a medication history, and assess the degree and severity of the patient's symptoms. Laboratory tests to measure insulin production and levels of C-peptide (a substance that the pancreas releases into the bloodstream in equal amounts to insulin) may be performed.
A diagnosis of reactive hypoglycemia is considered only after other possible causes of low blood sugar have been ruled out. Reactive hypoglycemia with no known cause is a condition in which the symptoms of low blood sugar appear 2 to 5 hours after eating foods high in glucose.
Ten to 20 years ago, hypoglycemia was a popular diagnosis. However, studies now show that this condition is actually quite rare. In these studies, most patients who experienced the symptoms of hypoglycemia after eating glucose-rich foods consistently had normal levels of blood sugar--above 60 mg/dL. Some researchers have suggested that some people may be extra sensitive to the body's normal release of the hormone epinephrine after a meal.
People with symptoms of reactive hypoglycemia unrelated to other medical conditions or problems are usually advised to follow a healthy eating plan. The doctor or dietitian may suggest that such a person avoid foods high in carbohydrates; eat small, frequent meals and snacks throughout the day; exercise regularly; and eat a variety of foods, including whole grains, vegetables, and fruits.