Evaluation of the Pancreas
For suspected pancreatic disease, obtain serum lipase (preferred) or serum amylase (≥4 times upper limit of normal) for acute pancreatitis diagnosis, followed by abdominal ultrasound as the initial imaging study, then proceed to pancreatic protocol CT or MRI based on clinical suspicion for acute pancreatitis, chronic pancreatitis, pancreatic cancer, or exocrine pancreatic insufficiency. 1
Initial Biochemical Testing
For Acute Pancreatitis Diagnosis
Serum lipase is the preferred initial test because it remains elevated longer than amylase, has higher specificity with no other serum sources, and maintains diagnostic accuracy in alcoholic pancreatitis and delayed presentations 1, 2, 3
Serum amylase ≥4 times the upper limit of normal confirms acute pancreatitis in the appropriate clinical setting, though it has lower specificity than lipase and normalizes more quickly 1, 4, 3
Both tests have similar sensitivity (72-79%) and specificity (89-93%) at standard thresholds, meaning approximately 1 in 4 patients with acute pancreatitis may have normal results, and 1 in 10 patients without pancreatitis may test positive 3
Daily enzyme measurements after diagnosis provide no value for assessing clinical progress or prognosis and should be discontinued 2
Baseline Laboratory Panel
- Obtain serum amylase or lipase, triglyceride level, calcium level, liver chemistries, glucose, HbA1c, and fat-soluble vitamin levels at initial evaluation 1, 5
Initial Imaging Strategy
Abdominal Ultrasound First
Perform abdominal ultrasound immediately in all patients with suspected pancreatic disease to evaluate the liver, bile ducts, and pancreas 1, 6
Ultrasound detects gallstones (critical for identifying gallstone pancreatitis requiring urgent ERCP), bile duct dilatation, free peritoneal fluid, and liver metastases 1, 7
The pancreas is poorly visualized in 25-50% of cases, so ultrasound cannot definitively exclude pancreatic disease 1
Advanced Cross-Sectional Imaging
CT Scanning
Pancreatic protocol CT (multiphasic with arterial, late arterial, and venous phases) is the primary imaging modality for diagnosing and staging pancreatic disease when ultrasound is inconclusive or clinical suspicion remains high 1, 6
Dynamic contrast-enhanced CT should be performed within 48 hours if acute pancreatitis is suspected but diagnosis remains uncertain 1
In severe acute pancreatitis, repeat CT every 2 weeks (or more frequently if sepsis develops) to detect pancreatic necrosis, fluid collections, and complications 1
CT has 70-85% sensitivity for detecting pancreatic cancer and is the standard for staging 6
MRI with MRCP
Use MRI with gadolinium plus MRCP when CT is contraindicated, to distinguish solid from cystic lesions, or when superior detection of small hepatic/peritoneal metastases is needed 1, 6, 7
MRCP provides detailed ductal imaging and clarifies diagnostic uncertainty between chronic pancreatitis and cancer without the pancreatitis risk of ERCP 7
Endoscopic Ultrasound (EUS)
EUS is superior to CT/MRI for detecting small pancreatic tumors (<2 cm), assessing vascular invasion, and obtaining tissue diagnosis via fine-needle aspiration 6, 7
EUS-guided FNA is preferred over percutaneous biopsy due to lower bleeding risk and no peritoneal seeding risk 7
Consider EUS when imaging is equivocal or tissue diagnosis is needed before non-surgical treatment 1, 6
Evaluating for Exocrine Pancreatic Insufficiency (EPI)
High-Risk Populations Requiring Testing
Test patients with chronic pancreatitis, recurrent acute pancreatitis, pancreatic cancer, cystic fibrosis, or previous pancreatic surgery 1, 5
Consider testing in moderate-risk conditions: celiac disease, Crohn's disease, longstanding diabetes, or previous intestinal surgery 1
Patients with total pancreatectomy require no testing and should start pancreatic enzyme replacement therapy immediately 5
Fecal Elastase-1 Testing
Fecal elastase-1 (FE-1) is the initial diagnostic test for EPI, performed on semi-solid or solid stool (not liquid/watery stool) 1, 5
FE-1 <100 μg/g confirms EPI; values 100-200 μg/g are indeterminate and should prompt repeat testing 1, 5
FE-1 can be performed while on pancreatic enzyme replacement therapy, as PERT does not alter results 1, 5
Do not use repeat FE-1 to monitor treatment response, as it does not change with therapy 5
Specific Clinical Scenarios
Suspected Pancreatic Cancer
Consider pancreatic cancer in adult-onset diabetes without predisposing factors or family history 1, 6
Exclude pancreatic cancer during investigation of any unexplained acute pancreatitis episode 1, 7
Histological confirmation is mandatory before non-surgical treatment but not required before curative surgery if imaging is typical 6
CA19-9 has limited diagnostic value and should not be used as a primary diagnostic tool 6
Differentiating Pancreatitis from Cancer
Liver metastases on imaging definitively exclude isolated pancreatitis 7
Vascular invasion/encasement and lymph node metastases favor cancer over pancreatitis 7
In chronic pancreatitis patients, strongly consider underlying carcinoma if no other etiology is identified 7
Common Pitfalls to Avoid
Do not rely on therapeutic trial of pancreatic enzymes as a diagnostic test for EPI, as response is unreliable 1, 5
Do not perform FE-1 on liquid stool, as results will be inaccurate 5
Do not assume normal amylase/lipase excludes acute pancreatitis in hyperlipidemic pancreatitis, chronic pancreatitis exacerbations, or delayed presentations—maintain low threshold for admission and treatment 3
Do not delay appropriate surgical treatment when clinical suspicion is high despite negative biopsy results 6, 7
Plain abdominal x-rays have unreliable findings (sentinel loop, colon cutoff sign) and cannot be recommended for pancreatic disease diagnosis 1
Chest x-ray should be obtained to establish baseline and exclude other pathology (pleural effusions, ARDS in severe cases) 1