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Acute Pancreatitis. ARUP Consult®. Retrieved June 19, 2025, https://arupconsult.com/content/pancreatitis-acute

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Acute Pancreatitis

Last Literature Review: May 2025 Last Update:

Educational Videos From ARUP Laboratories

Acute and Chronic Pancreatitis
46 min

Medical Experts

Contributor

Leonard

Picture of Nicole Leonard, MD
Nicole Leonard, MD
Anatomic and Clinical Pathology Resident, University of Utah School of Medicine and ARUP Laboratories
Contributor

Acute pancreatitis is a reversible inflammatory process of the pancreas caused by autodigestion that generally presents with epigastric abdominal pain that may radiate to the back and is worsened by the ingestion of food. Acute pancreatitis often resolves within a few days, but severe disease has a high mortality rate.  The most common causes of acute pancreatitis are gallbladder disease, alcohol use, and hypertriglyceridemia. In addition to abdominal pain, patients may present with nausea and vomiting, which are nonspecific, so imaging and laboratory testing are important to make a definitive diagnosis.  Lipase testing is the preferred laboratory approach for diagnosing acute pancreatitis, as lipase is the most sensitive and specific marker for pancreatic cell damage. , 

Quick Answers for Clinicians

What should be considered in the differential diagnosis of acute pancreatitis?

Abdominal pain, nausea, and vomiting are relatively nonspecific symptoms and may occur in a variety of situations. The differential diagnosis of acute pancreatitis includes but is not limited to acute cholecystitis, appendicitis, cholangitis, intestinal obstruction, gastric volvulus, mesenteric ischemia, nephrolithiasis, pancreatic cancer, perforated ulcer, diabetic ketoacidosis, acute coronary syndrome, aortic dissection, ectopic pregnancy, and tubo-ovarian abscess. Appropriate laboratory testing and imaging are essential for differentiating these conditions.

Which laboratory tests should be ordered when acute pancreatitis is suspected?

The recommended test to diagnose acute pancreatitis is lipase measurement. If the lipase concentration is more than three times the upper limit of normal (ULN), acute pancreatitis is highly likely. Although amylase measurement was originally preferred for acute pancreatitis and is still widely performed, it is less sensitive and specific than lipase testing and provides no additional clinical information. 

What is the role of risk scoring systems in acute pancreatitis?

Most risk scoring systems (e.g., Ranson, Imrie, and APACHE scoring systems) are not useful in determining which patients will progress to severe acute pancreatitis. Many scoring systems become accurate only after 48 hours and after the severity of disease is already clinically apparent.  Calculators that include blood urea nitrogen (BUN) measurement and the presence of systemic inflammatory response syndrome (SIRS) are more effective, but these risk scoring systems may not be more informative than measuring BUN and monitoring for the development of SIRS. 

Indications for Testing

Laboratory testing for acute pancreatitis is appropriate to support a diagnosis in patients with suspected acute pancreatitis and contribute to a prognosis.

Criteria for Diagnosis

According to the American College of Gastroenterology clinical practice guidelines, the definitive diagnosis of acute pancreatitis is typically established when two of the following criteria are met :

  • Epigastric abdominal pain
  • A serum lipase or amylase concentration >3 x the upper limit of normal (ULN); serum lipase is preferred
  • Imaging findings suggestive of pancreatic inflammation

Laboratory Testing

Diagnosis

The recommended test for acute pancreatitis is the serum lipase test. If the lipase concentration is greater than three times the ULN, a diagnosis of acute pancreatitis is highly likely. However, lipase can be elevated in nonpancreatic conditions (e.g., diabetes); therefore, a lipase concentration three to five times greater than the ULN may be required for diagnosis.  Serum lipase levels increase within 4-8 hours of acute pancreatitis onset and remain elevated for 8-14 days. Serial measurements are not necessary as they do not provide prognostic information. The degree of elevation does not correlate with prognosis. 

Lipase measurement is more sensitive and specific for pancreatic disease than amylase measurement.  Amylase measurement is no longer recommended for the diagnosis of acute pancreatitis; lipase testing offers improved sensitivity and specificity because amylase is secreted by organs other than the pancreas.  Serum amylase is initially elevated but returns to normal in 48-72 hours in patients with acute pancreatitis. 

Increased lipase and amylase concentrations without abdominal pain or suggestive imaging findings do not predict the development of acute pancreatitis. 

Prognosis

Estimating severity and assessing prognosis in acute pancreatitis are difficult early in disease development. Serial hematocrit (HCT) and blood urea nitrogen (BUN) measurements are useful to predict the development of severe disease and potential organ failure as increases of HCT and BUN in the first 24 hours can reliably predict mortality and persistent multiorgan failure in patients with acute pancreatitis.  C-reactive protein (CRP) measurement is not helpful for prognosis because CRP takes 48-72 hours to become a reliable factor in risk assessment of severe acute pancreatitis. Several severity scoring systems exist but many become accurate only after 48 hours, which limits their utility.  The main risk factors of severe disease are indicators of systemic inflammatory response syndrome (SIRS) and signs of hypovolemia, such as elevated HCT and elevated BUN measurements. 

ARUP Laboratory Tests

Diagnosis
Prognosis

Panel includes albumin; alkaline phosphatase; AST; ALT; bilirubin, total; calcium; carbon dioxide; creatinine; chloride; glucose; potassium; protein, total; sodium; and urea nitrogen

References