Diagnostic Approach for Suspected Pancreatic Inflammation

Initial Diagnostic Tests

The American Gastroenterological Association recommends ordering serum lipase as the primary diagnostic test for suspected acute pancreatitis, with a diagnostic threshold of ≥3 times the upper limit of normal, due to its superior sensitivity (79-89%) and specificity (89-94%) compared to amylase 1, 2
Lipase has a larger diagnostic window than amylase, rising within 4-8 hours of pancreatic injury, peaking at 24 hours, and remaining elevated for 8-14 days 1, 2
The American Gastroenterological Association suggests that ordering both lipase and amylase together provides no diagnostic advantage 2

Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) should be ordered at admission to evaluate for gallstone etiology and biliary obstruction 1, 3
Serum triglycerides should be ordered, with levels >1000 mg/dL indicating hypertriglyceridemia-induced pancreatitis 1, 2
Serum calcium should be ordered to identify hypercalcemia as a cause of pancreatitis 1, 2
A complete blood count should be ordered for white blood cell elevation 4
C-reactive protein (CRP) should be ordered, with CRP ≥150 mg/L at 48 hours predicting severe disease 1, 3

Abdominal ultrasound should be ordered at admission to look for gallstones or bile duct obstruction 1, 3
CT with IV contrast should be ordered after 72 hours if predicted severe disease or APACHE II score >8 to assess for pancreatic necrosis 1, 3

If autoimmune pancreatitis is suspected, serum IgG4 level should be ordered, with a level >280 mg/dL being diagnostic for type 1 autoimmune pancreatitis 5