A 55-year-old woman presents with severe right upper quadran…

A 55-yeаr-оld wоmаn presents with severe right upper quаdrant pain that began fоur hours after eating a cheeseburger. She reports nausea but no vomiting. Temperature is 100.2°F (37.9°C). On examination she has focal right upper quadrant tenderness. Which additional physical examination finding would most strongly increase your suspicion for acute cholecystitis?