Review Question - QID 210063

A 27-year-old man presents to the emergency department with abdominal pain. He was at home working when he felt the pain steadily worsen, thus prompting his presentation. The patient has a medical history of asthma treated with albuterol. His temperature is 98.5°F (36.9°C), blood pressure is 147/88 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam is notable for epigastric pain worsened with palpation. Inspection of the patient reveals the finding in Figure A. The patient’s gait is unsteady and his breath smells of alcohol. The patient is started on IV fluids and morphine. Which of the following is the most appropriate diagnostic test for the underlying etiology of this patient’s presentation?