MSFinals-6228
A 42-year-old male presents to the emergency department with intermittent abdominal pain in the right upper quadrant (RUQ). The pain started 3 hours ago, and is described as a sharp pain that comes and goes. The pain does not radiate anywhere, but it has progressively worsened throughout the day.
Upon examination, the patient appears to be in pain at rest, but does not appear clammy or pale. He is very tender in the right upper quadrant, but no guarding or rebound tenderness is felt.
His vital signs are as follows:
Heart rate = 105 beats per minute.
Respiratory rate = 20 breaths per minute.
Blood pressure = 130/85 mmHg.
Temperature = 38.5ºC.
What is the most appropriate next investigation to perform?