The blood amylase test is ordered, often along with a lipase test, to help diagnose and monitor acute or chronic pancreatitis (inflammation of the pancreas) and other disorders that may involve the pancreas. A urine amylase test may also be ordered. Typically, its level will mirror blood amylase concentrations, but both the rise and fall occur later. Sometimes a urine creatinine clearance may be ordered along with the urine amylase to help evaluate kidney function since decreased kidney function can result in a slower rate of amylase clearance.

Amylase tests are sometimes used to monitor treatment of some cancers involving the pancreas and after removal of gallstones that have caused gallbladder attacks.

A blood amylase test may be ordered when a patient has symptoms of a pancreatic disorder, such as severe abdominal pain, fever, loss of appetite, or nausea. A urine amylase test may be ordered along with or following a blood amylase test. One or both may also be ordered when a doctor wants to monitor a patient to evaluate the effectiveness of treatment and to determine whether amylase levels are increasing or decreasing over time.

In acute pancreatitis, amylase in the blood increases (often to 4-6 times higher than the highest reference value, sometimes called upper limit of normal). The increase occurs within 12 hours of injury to the pancreas and generally remains elevated until the cause is successfully treated. Then the amylase values will return to normal in a few days. In chronic pancreatitis, amylase levels initially will be moderately elevated but often decrease over time with progressive pancreas damage.

Amylase levels may also be significantly increased in patients with pancreatic duct obstruction, cancer of the pancreas, and gallbladder attacks. Urine and blood amylase levels may also be elevated with a variety of other conditions, such as ovarian cancer, lung cancer, tubal pregnancy, mumps, intestinal obstruction, or perforated ulcer, but amylase tests are not generally used to diagnose or monitor these disorders. Decreased blood and urine amylase levels may indicate permanent damage to the amylase-producing cells in the pancreas. Increased blood amylase levels with normal to low urine amylase levels may indicate decreased kidney function or the presence of a macroamylase, a benign complex of amylase and other proteins that accumulates in the blood.

Since reference values for amylase vary from laboratory to laboratory, depending on the test method used, there is no universally accepted number that can be called normal or high.

In acute pancreatitis, elevated amylase levels usually parallel lipase concentrations, although lipase levels may take a bit longer to rise than blood amylase levels and will remain elevated longer.

Chronic pancreatitis is often associated with alcoholism. It may also be caused by trauma, pancreatic duct obstruction, and seen in association with genetic abnormalities such as cystic fibrosis. Amylase levels may be moderately elevated with chronic pancreatitis but often decrease over time with progressive pancreas damage.