Q. A 34-year-old nurse presents to your clinic with a chief complaint of recurrent episodes of hypoglycemia. She reports experiencing dizziness, weakness, and confusion when her blood sugar levels dropped, and has been monitoring her blood sugar levels at home using a glucometer. She denies any history of alcohol or substance abuse. Her past medical history is significant for generalized anxiety disorder. The patient is not currently taking any medications. On physical examination, the patient appears to be in good health, with a normal body mass index and no signs of overt illness. Laboratory studies show low blood glucose levels. You are concerned about the possibility of endogenous hyperinsulinemia, which would be consistent with a diagnosis of factitious hypoglycemia. Which of the following laboratory results would confirm your suspicion?