This test is used to measure level of lipase in blood. Lipase is an enzyme produced by the pancreas, which is a large gland situated near the stomach. The lipase test is most often used in evaluating inflammation of the pancreas (pancreatitis), but it is also useful in diagnosing kidney failure, intestinal obstruction, mumps, and peptic ulcers. Doctors often order amylase and lipase tests at the same time to help distinguish pancreatitis from ulcers and other disorders in the abdomen. If the patient has acute (sudden onset) pancreatitis, the lipase level usually rises somewhat later than the amylase level-about 24-48 hours after onset of symptoms-and remains abnormally high for 5-7 days. Because the lipase level peaks later and remains elevated longer, its determination is more useful in late diagnosis of acute pancreatitis. Conversely, however, lipase levels are not as useful in diagnosing chronic pancreatic disease.