Plasma glucose responses to glucagon after a prolonged fast

Relationship between the plasma glucose concentration after a prolonged fast and the increase in plasma glucose after the administration of 1 mg of intravenous glucagon in normal subjects and patients with an insulinoma. In patients who become hypoglycemic, an increase in plasma glucose of ≥25 mg/dL (1.4 mmol/L) after glucagon is suggestive of an insulinoma. To convert plasma glucose values to mmol/L, multiply by 0.056.