A test used to measure the ability of the pancreas to respond to a hormone called secretin. Secretin causes the pancreas, liver, and stomach to release substances that help digest food. During a pancreatic function test, a tube is inserted through the nose or throat into the stomach and small intestine. Secretin is given to the patient by injection into a vein. After a certain amount of time, samples of fluid are taken from the small intestine through the tube and sent to a lab to test for a response. A pancreatic function test may be used to help diagnose problems that affect the pancreas, such as pancreatitis, cystic fibrosis, and a type of pancreatic tumor called a gastrinoma. Also called secretin stimulation test.