Amylase

Specimen:

5 mL blood in lithium heparin or plain tube.

Method:

Spectrophotometry.

Reference Interval:

Method dependent.

Racial differences have been reported.

Some laboratories offer a specific pancreatic amylase assay - consult pathologist.

Application:

Clinical suspicion of acute pancreatitis. Lipase or specific pancreatic amylase are the preferred tests.

Interpretation:

Very high levels are found with acute pancreatitis; lipase is a more sensitive and specific indicator of this disorder.

A normal amylase level does not exclude acute pancreatitis. The test is not specific, with very high levels being found in pancreatic pseudocyst, perforated duodenal ulcer and upper small bowel obstruction.

Moderately high levels are found frequently in other acute abdominal conditions.

High levels are also found in acute parotitis and macroamylasaemia, a clinically insignificant disorder described in 1.5% of (non-alcoholic) hospitalised adult patients.

Assays which are specific for the pancreatic isoenzyme improve the specificity of the test.

See also Lipase.

Reference:

Yadav D et al. Am J Gastroenterol 2002; 97: 1309-1318.