How is hypoglycemia diagnosed? - Diabetic Hypoglycemia Diagnosis and Tests

How is hypoglycemia diagnosed?

Blood glucose can be easily measured by blood testing in a doctor's office. Home test kits are also available for rapid glucose measurement. These home test kits are designed for use by diabetics to monitor and regulate their blood glucose at home while taking insulin or oral glucose-lowering agents. Doctors first measure the level of sugar in the blood. A low sugar level in the blood found at the time a person is experiencing typical symptoms of hypoglycemia confirms the diagnosis
in a person without diabetes, especially if the relationship between a low sugar level in the blood and symptoms is demonstrated more than once. If symptoms are relieved as the sugar levels in the blood rise within a few minutes of ingesting sugar, the diagnosis is supported.
In those who do not have diabetes, diagnosis requires demonstration of low blood glucose levels accompanied by the usual symptoms. Depending on the type of hypoglycemia, blood glucose is measured either during a glucose tolerance test or after an overnight fast. Further tests and a detailed patient history are then necessary to determine the underlying cause of hypoglycemia. Those with diabetes can verify and document episodes of hypoglycemia with home blood glucose monitoring.

Since symptoms of hypoglycemia are vague and often non-specific, many other conditions can mimic hypoglycemia. In order to establish hypoglycemia as the cause of the patient's symptoms, three criteria must be met. The patient must have symptoms of hypoglycemia with a documented blood glucose level of less than 45 mg/dl. Additionally, the symptoms have to resolve completely with the administration of glucose. These diagnostic criteria are referred to as "Whipple's triad."

When medications, such as diabetes medicines, cause hypoglycemia, it can be discovered by reviewing the patient's history of taking excessive medication, or by measurement of the level of medications in the blood. When insulin-producing tumors are responsible for hypoglycemia the diagnosis can be made by finding excess insulin and its byproducts in the blood. In patients suspected of having reactive hypoglycemia, the 5- hour glucose tolerance test is not as useful as directly measuring the blood glucose levels or performing home glucose monitoring when symptoms occur.