What is Amylase - Body fluids?

Amylase is an enzyme produced primarily by the pancreas and the salivary glands to help digest carbohydrates. This test measures the amount of amylase in the blood or urine or sometimes in peritoneal fluid, which is a fluid found between the membranes that cover the abdominal cavity and the outside of abdominal organs.

The pancreas is a narrow, flat organ about six inches long located deep within the abdominal cavity, below the liver, and between the stomach and the spine. Its head section connects to the duodenum, the first part of the small intestine. Inside the pancreas, small ducts (tubes) feed digestive enzymes produced by the pancreas into the pancreatic duct. The pancreas releases amylase through the pancreatic duct into the first part of the small intestine, where it helps break down dietary carbohydrates.

Amylase is usually present in the blood and urine in small quantities. When cells in the pancreas are injured, increased amounts of amylase are released into the blood. This also increases concentrations of amylase in the urine because amylase is eliminated from the blood through the urine. Increased amylase levels can occur with pancreatitis or when the pancreatic duct is blocked by a gallstone or, in rare cases, with a pancreatic tumor.

How is the test used?

The blood amylase test is used to help diagnose and monitor acute pancreatitis. It may also be used to diagnose and monitor chronic pancreatitis and other disorders that may involve the pancreas.

The blood amylase test may be used along with a lipase test to detect pancreatic diseases. While the amylase test is sensitive for pancreatic diseases, it is not specific. That means an elevated amylase level may indicate a problem, but the cause may not be related to the pancreas. The lipase test, on the other hand, is more specific than amylase for diseases of the pancreas, particularly for acute pancreatitis and for acute alcoholic pancreatitis. An elevated lipase usually indicates a problem with the pancreas. Evaluating the results of the two tests together helps to diagnose or rule out pancreatitis and other conditions.

A urine amylase test may also be used to detect pancreatic diseases. Typically, its level will mirror blood amylase concentrations, but both the rise and fall will occur later. Sometimes a urine creatinine level may be ordered along with the urine amylase. The ratio of amylase to creatinine can be calculated and used to assess kidney function. Kidney dysfunction can result in a slower rate of amylase clearance.

In certain cases, for example, when there is an accumulation of fluid in the abdomen (ascites), an amylase test may be performed on peritoneal fluid to help make a diagnosis of pancreatitis.

Amylase tests are sometimes used to monitor the treatment of pancreatic cancer and after the removal of gallstones that have caused gallbladder attacks.