PANRE Practice Test 6

A 20-year-old woman comes to the student health clinic because of fatigue and palpitations for 2 weeks. On direct questioning she reports episodes of eating large amounts of food in a short time several times a week for 1 year, each followed by self-induced vomiting. She denies laxative or diuretic use. Height is 165 cm (5 ft 5 in), and weight is 59 kg (130 lb). Temperature is 36.6°C (97.9°F), heart rate is 96/min, respirations are 14/min, blood pressure is 104/66 mmHg, and oxygen saturation is 99% on room air. Examination shows bilateral painless parotid enlargement, erosion of the lingual surfaces of the upper incisors and calluses on the dorsum of the right hand. Which of the following laboratory findings is most likely?