A 48-year-old female with a history of mild congestive heart failure (CHF) treated with furosemide presents to the emergency room (ER) for evaluation of 24 hours of epigastric pain, nausea, and vomiting after eating a large meal in a restaurant. Previously, the patient had experienced intermittent right upper quadrant pain after eating. On examination, the patient has a temperature of 98.5 and a pulse of 100. Her examinat ion is remarkable for epigastric tenderness to palpation, normal bowel sounds, and no rebound tenderness or guarding.
Laboratory studies are as follows:
Leukocyte count 4800/mm3
Alanine aminotransferase (ALT) 258 U/L
Aspartate aminotransferase (AST) 287 U/L
Alkaline phosphatase, serum 350 U/L
Bilirubin (total) 2.0 mg/dL
Bilirubin (indirect) 0.4 mg/dL
Amylase 2865 U/L
Lipase 3453 U/L
What would the most appropriate next test to order be?