Review Question - QID 212759

A 39-year-old woman is brought to the emergency room by her fiancé for severe abdominal pain for the past 5 hours. She was watching TV after dinner when she felt a sudden, sharp, 10/10 pain at the epigastric region that did not go away. Ibuprofen also did not help. She reports recurrent abdominal pain that would self-resolve in the past but states that “this one is way worse.” Her past medical history is significant for diabetes and an appendectomy 2 years ago. The patient endorses nausea and 1 episode of emesis, but denies fevers, chills, chest pain, shortness of breath, diarrhea, constipation, urinary symptoms, paresthesia, or weakness. She used to smoke marijuana in college and drinks about 2 beers a week. A physical examination demonstrates an overweight woman in acute distress with diffuse abdominal tenderness. Her vitals are within normal limits. Laboratory values are shown below:

Hemoglobin: 12 g/dL
Hematocrit: 34%
Leukocyte count: 4,900/mm^3 with normal differential
Platelet count: 160,000/mm^3

Serum:
Na+: 138 mEq/L
Cl-: 98 mEq/L
K+: 4.8 mEq/L
HCO3-: 25 mEq/L 
Glucose: 123 mg/dL
Ca2+:  6.9 mg/dL
AST: 387 U/L
ALT: 297 U/L
ALP: 168 U/L
Lipase: 650 U/L (Normal 0 – 160 U/L)

What is the best next step in the workup of this patient?