5 Days Of Right in Medicine / Internal Medicine — Case | Hepatology | SMLE Q#18417

A 28-year-old previously healthy man presents to the emergency department with 5 days of right upper quadrant abdominal pain with nausea and 2 episodes of vomiting. Two days later, his family noticed yellow discoloration of his eyes and skin. He denies alcohol use, acetaminophen overdose, and illicit drugs. On exam, he is jaundiced with right upper quadrant tenderness. Vital signs: - T: 37.2 °C - BP: 122/76 mmHg - HR: 88 /min - RR: 16 /min - SpO2: 98% (room air) Lab results: - Alkaline phosphatase: 109 U/L (39–117) - ALT: 990 IU/L (5–40) - AST: 789 IU/L (12–40) Which of the following is the most appropriate next step in diagnosis?