Yes. In a non diabetic person, suspected hypoglycemia needs to be confirmed with a fasting test. Because of the risks, the test has to done in a hospital, where the patient can be monitored. When and if the blood sugar drops, the Insulin is measured, to understand whether the condition is cause by unregulated Insulin secretion.
Hypoglycemia. We diagnose hypoglycemia if a patient has (1) appropriate symptoms of hypoglycemia, (2) documented low blood sugar, either by fingerstick or lab test, and (3) appropriate positive response (resolution of symptoms) with administration of glucose/sugar. Can be confirmed by an oral glucose tolerance test, performed in a lab.