What pancreatic blood work is recommended for a patient presenting with symptoms suggestive of pancreatic disorders?

Pancreatic Blood Work for Suspected Pancreatic Disorders

For patients with symptoms suggestive of pancreatic disorders, obtain serum lipase (preferred) or amylase, liver function tests (bilirubin, AST, ALT, alkaline phosphatase), serum triglycerides, and serum calcium as initial blood work. 1, 2

Acute Pancreatic Disease Evaluation

Primary Diagnostic Markers

• Serum lipase is the preferred first-line test for acute pancreatitis diagnosis, with a diagnostic cutoff of ≥3 times the upper limit of normal, due to superior performance characteristics compared to amylase 1, 2
• Serum amylase can serve as an alternative to lipase but has less specificity and a shorter diagnostic window; use the same cutoff of ≥3 times the upper limit of normal 1
• Both enzymes should be measured at presentation when acute pancreatitis is suspected 3

Etiology Determination

• Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) help identify biliary pancreatitis as the underlying cause 2
• Fasting serum triglycerides should be obtained to exclude hypertriglyceridemia as a cause of pancreatitis 2
• Serum calcium measurement is necessary to detect hypercalcemia as a potential etiology 2

Severity Assessment and Prognostic Markers

When acute pancreatitis is confirmed, additional blood work predicts disease severity:

• C-reactive protein (CRP) at 48-72 hours, with values ≥150 mg/L predicting severe disease 1, 2
• Hematocrit >44% serves as an independent risk factor for pancreatic necrosis 1, 2
• Blood urea nitrogen (BUN) >20 mg/dL predicts mortality 1, 2
• Procalcitonin is the most sensitive marker for detecting pancreatic infection, with low values strongly excluding infected necrosis 1, 2

Chronic Pancreatic Insufficiency Evaluation

What NOT to Order

Do not order serum pancreatic enzymes (lipase, amylase, or trypsin) for diagnosing chronic pancreatitis or pancreatic insufficiency, as these lack sensitivity until disease is far advanced 1, 4

Recommended Testing

• Fecal elastase-1 is the recommended first-line test for chronic pancreatic insufficiency due to its convenience, reliability, and lack of interference from diet or enzyme supplementation 5, 1, 4
• Values <200 μg/g indicate abnormal pancreatic function 5, 4
• Values <100 μg/g suggest moderate to severe pancreatic insufficiency 5, 2, 4
• Values <50 μg/g are most reliable for severe exocrine pancreatic insufficiency 5, 2

Clinical Context Considerations

Presenting Symptoms Guide Testing Strategy

For patients presenting with:

• Acute abdominal pain radiating to the back: Order serum lipase/amylase immediately 5, 3
• Weight loss, floating stools, diarrhea: Order fecal elastase-1 as initial test 5, 4
• Jaundice: Include liver function tests to assess for biliary obstruction 5, 2
• New-onset diabetes in otherwise fit individuals: Consider early pancreatic cancer screening with CA 19-9 and imaging 5

Important Caveats

• Normal serum amylase and lipase effectively exclude acute pancreatitis but do not rule out chronic pancreatic disease or malignancy 4
• Serum enzyme levels can be falsely elevated in chronic liver disease, particularly cirrhosis, due to decreased hepatic metabolism 6
• Do not initiate empiric pancreatic enzyme replacement as a diagnostic test, as symptomatic improvement is unreliable and nonspecific, potentially masking other disorders like celiac disease 4

Tumor Marker Consideration

• CA 19-9 should be obtained in the workup of suspected pancreatic adenocarcinoma, particularly when imaging suggests a pancreatic mass 5
• Post-treatment CA 19-9 levels help monitor for disease progression 5

Micronutrient Assessment in Established Disease

For patients with confirmed exocrine pancreatic insufficiency:

• Annual assessment of fat-soluble vitamins (A, D, E, K) and micronutrient status 5
• Annual endocrine function check including fasting glucose and HbA1c 5