Amylase and lipase are digestive enzymes produced by the pancreas. Amylase and lipase tests are used to distinguish acute appendicitis from acute pancreatitis. Both tests are done on blood, but amylase may also be tested from a urine sample. Elevation of these enzymes may indicate mumps, renal failure, alcoholic liver disease or other conditions.
Normal Lab Values
Normal values may vary slightly from one lab to another; however these values give an idea of an acceptable range. The lab will give their normal ranges as a reference value.
A normal amylase value is 30-100 U/liter in adults,while a normal value for lipase is 10-140 U/liter. Many medications and medical conditions can affect the results. Blood thinners, narcotics, diabetes, kidney disease, high blood pressure, and high cholesterol may affect the test so that the results are not reliable.
Causes of Increased Amylase
Acute pancreatitis is one of the most common reasons for amylase testing. Other causes of increased amylase levels include pancreatic duct obstruction, alcohol use, mumps, kidney disease, and peptic ulcers. Amylase levels in acute pancreatitis start to rise two to twelve hours after the onset of severe abdominal pain. Levels may be as high as six times the normal range. Levels peak in 12 to 72 hours, and are back to normal by four days.
Causes of Decreased Amylase
Lower than normal amylase levels can indicate liver damage or destructive pancreatitis as well as cystic fibrosis. There are many more causes of increased levels than decreased levels.
Causes of Increased Lipase
The pancreas is the only organ in the body that secretes lipase; therefore, increased lipase levels indicate a variety of pancreas conditions. Lipase is stored in the pancreatic tissue and is released when damage occurs to the pancreas. High levels may also indicate kidney failure, since the kidneys excrete lipase. Like amylase, many drugs can increase the lipase level.
Which One is Best?
Amylase and lipase are usually ordered together in order to diagnose pancreatitis, with the lipase being more accurate.
It's important to remember that a diagnosis cannot be made on one lab value alone. Physical exam, medical history, medication history and other labwork need to be consulted for a definitive diagnosis.