Pancreatic elastase is a form of elastin produced in the acinar cells of the pancreas, and fecal immunoreactive elastin (elastase-1) has been used to diagnose many pancreas-related diseases, such as pancreatitis and pancreatic cancer. Due to cell necrosis of the pancreas or blockage of the pancreatic duct, elastase-1 can be released into the stool. Elastase-1 has also been studied for the diagnosis of other pancreatic diseases, and its clinical applications are also increasing, such as the evaluation of pancreatic exocrine insufficiency.