Question: An 82-year-old woman arrived in our emergency department for acute right upper abdominal pain with no trauma history. She had a medical history of cardiac arrhythmia (atrial fibrillation) with pacemaker insertion and anticoagulant therapy (warfarin 2.5 mg/d). At the time of her presentation Prothrombin time was 36.8 s, prothrombin activity was 21%, international normalized ratio was 3.32, and platelet count was normal (247 × 103/μL). There was no alteration in liver function tests.