Labs
CBC
Chemistry
LFTs
Lipase
Lactate
Consider UA
CTA abdomen/pelvis (Bowel wall edema is the most common finding on CT)<unk>  angiography considered gold standard (if available, typically as a secondary study)
CBC
Chemistry
LFTs
Lipase
Lactate
Consider UA
Typically diagnosed on CT
Labs may show the following (although do not rule need for CT):
Lactate (higher later)
WBC (often >15K)
Chemistry (metabolic acidosis)
Hyperphosphatemia
Lactate (higher later)
WBC (often >15K)
Chemistry (metabolic acidosis)
Hyperphosphatemia
Mesenteric ischemia
Infectious colitis
Intestinal ischemia
Ischemic colitis
Large bowel obstruction
Ulcerative colitis
Malignant bowel obstruction
CMV colitis