CBC
Chem
LFTs
Lipase
Coags
Urinalysis
Urine pregnancy (female)
ECG (>40 yo)
Guaiac
?Lactate
?CT abd/pelvis
Diffuse abdominal pain
Abdominal aortic aneurysm
Epigastric abdominal pain
Aortocaval fistula
Abdominal pain 
Acute gastroenteritis
Abdominal pain
Aortoenteric fisulta