What blood tests are included in a pancreatic workup?

Blood Tests for Pancreatic Workup

A comprehensive pancreatic workup should include serum amylase or lipase, triglyceride level, calcium level, liver function tests (bilirubin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase), and C-reactive protein. 1

Core Laboratory Tests for Pancreatic Evaluation

Diagnostic Enzymes

• Serum amylase and/or lipase are the primary diagnostic tests for acute pancreatitis, with a threshold concentration of 2-4 times the upper limit of normal recommended for diagnosis 2
• Lipase is now preferred over amylase due to its improved sensitivity, particularly in alcohol-induced pancreatitis, and its prolonged elevation creates a wider diagnostic window 2
• Trypsinogen and elastase measurements have no significant advantage over amylase or lipase in routine clinical practice 2

Etiological Assessment

• Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) should be obtained to evaluate for biliary causes of pancreatitis 1
• Serum triglyceride levels should be measured to rule out hypertriglyceridemia as a cause (levels >11.3 mmol/L or >1000 mg/dL indicate this etiology) 1
• Serum calcium levels should be checked to evaluate for hypercalcemia as a potential cause 1

Severity Assessment

• C-reactive protein (CRP) is the most widely used severity marker, with levels ≥150 mg/L at 48 hours after disease onset indicating severe disease 1
• Hematocrit >44% represents an independent risk factor for pancreatic necrosis 1
• Blood urea nitrogen >20 mg/dL is an independent predictor of mortality 1
• Procalcitonin is the most sensitive laboratory test for detection of pancreatic infection, with low values being strong negative predictors of infected necrosis 1

Additional Tests for Specific Clinical Scenarios

For Suspected Pancreatic Cancer

• CA 19-9 tumor marker should be included when pancreatic malignancy is suspected 1
• Fasting glucose or HbA1c may be valuable as new-onset diabetes can be an early warning sign of pancreatic cancer 1

For Chronic Pancreatitis Evaluation

• Serum trypsin levels may be helpful in advanced chronic pancreatitis, though sensitivity is poor in early disease 1
• Fecal elastase testing is recommended as the first-choice test for suspected exocrine pancreatic insufficiency 1

Clinical Pearls and Pitfalls

• A normal amylase level does not exclude acute pancreatitis, particularly in cases of hypertriglyceridemia, acute exacerbation of chronic pancreatitis, or when testing is delayed after symptom onset 3
• Daily measurements of pancreatic enzymes after diagnosis have no value in assessing clinical progress or prognosis and should be avoided 3
• Serum enzyme quantification (lipase, trypsin, amylase) is not valuable for diagnosing chronic pancreatitis as levels may remain normal until very advanced disease 1
• In patients with a single episode of unexplained pancreatitis who are younger than 40 years, extensive laboratory evaluation is not recommended 1

Timing of Laboratory Tests

• Initial laboratory tests should be obtained at admission 1
• CRP should be measured at 48 hours after symptom onset for optimal prognostic value 1
• If triglyceride levels cannot be obtained at admission, fasting levels should be measured after recovery when the patient has resumed normal intake 1

Remember that laboratory tests should be interpreted in conjunction with clinical findings and appropriate imaging studies for a complete pancreatic workup 4.