Evaluate parotitis and pancreatic disease. Amylase is primarily produced in the pancreas and salivary glands. Isoenzymes may be used to determine the source of an elevated amylase concentration. Measurement of pancreatic amylase activity is of value in diagnosing pancreatitis and other pancreatic disorders that result in the elevation of serum and urine amylase.
Patients with macroamylase may have elevated pancreatic amylase results. The elevation is due to the higher than normal level of pancreatic amylase in the macroimmune complex. This elevated pancreatic amylase is not diagnostic for pancreatitis, however, measurement of an elevated pancreatic amylase in urine is confirmatory of pancreatitis, pancreatic trauma, or pancreatic carcinoma since macroamylases are too large for renal clearance (see Additional Information).
Macroamylases are sometimes present in sera. These rare forms are probably complexes between ordinary amylase (usually S-type) and IgA, IgG, or other high molecular weight plasma proteins. These macroamylases cannot be filtered through the glomeruli of the kidney because of their large size (MW >200,000) and are thus retained in the plasma where their presence may increase amylase activity to some six- to eightfold over that observed in health. In macroamylasemia, amylase activity in the urine is lower than normal, since less amylase is cleared by the kidneys. No clinical symptoms are associated with this disorder; however, many of these cases have been detected following investigation of abdominal pain.