Fecal elastase is a specific marker for pancreatic function and maintains a high diagnostic accuracy among patients with small intestinal diseases. This pancreatic elastase marker allows for the diagnosis or exclusion of pancreatic exocrine insufficiency and degree of severity, which can be caused by chronic pancreatitis, cystic fibrosis, pancreatic tumor, cholelithiasis or diabetes mellitus. This pancreatic elastase test does not differentiate between pancreatic insufficiency due to chronic pancreatitis and that due to pancreatic cancer.