The blood test for amylase is used to diagnose acute pancreatitis (inflammation of the pancreas) and other pancreatic diseases. The swift rise of amylase at the beginning of a pancreatitis attack, and its fall after about 2 days, helps to pinpoint this diagnosis. Amylase is sometimes although rarely used in the diagnosis and follow-up of cancer of the pancreas, gallbladder disease and mumps.

An amylase test may be requested if you show symptoms of a pancreatic disorder, such as severe abdominal pain, fever, loss of appetite, or nausea. Urine amylase may be requested with or following a blood amylase test. One or both may also be requested when a doctor wants to monitor a patient to find out whether treatment is working and whether amylase levels are increasing or decreasing.

In pancreatitis which is a severe inflammation of the pancreas, amylase levels are usually very high, often 5-10 times normal. Increased amylase levels may also indicate cancer of the pancreas, gallbladder disease, a perforated ulcer, obstruction of the intestinal tract, mumps or ectopic pregnancy. Increased blood amylase levels with normal or low urine amylase levels may indicate decreased kidney function or the presence of macroamylase, when amylase is attached to other proteins and accumulates in blood. High amylase levels due to macroamylase is not a indicator of disease.

In acute pancreatitis, elevated amylase levels usually parallel levels of another enzyme called lipase. Either amylase or lipase levels can be requested in order to help  diagnose acute pancreatitis.
Chronic (long-term) pancreatitis is often associated with alcoholism. It may also be caused by trauma to the pancreas or associated with genetic abnormalities such as cystic fibrosis. Amylase levels may be moderately elevated with chronic pancreatitis or may be decreased when the cells that produce amylase in the pancreas become damaged or destroyed.