title: Puzzling persistent hyperamylasemia, probably neither pancreatic nor pathologic.
abstract: Increased serum amylase levels most commonly signify pancreatic disease. One hundred seventeen consecutive patients were studied because their serum amylase levels were abnormally high for periods ranging from 3 to 48 weeks. In each case, extensive clinical and radiologic evaluation had failed to reveal a reason for the abnormality. The amylase isoenzymes of their sera were separated by polyacrylamide gel electrophoresis, and the fractions were measured by a saccharogenic assay. The findings in the 117 patients showed that 79 percent had non-pancreatic causes for their hyperamylasemia. The biggest single group (64 percent) had a normal distribution of isoamylases, albeit at unusually high concentrations. This phenomenon, which has not been defined previously, is probably a variant of normal in which the homeostatic balance between production and metabolism is set at a high level. Macroamylasemia accounted for 6 percent of the cases and salivary hyperamylasemia for only 9 percent. Three patients had the characteristic isoamylase pattern ("old amylase") associated with pancreatic pseudocysts. Isoamylase fractionation is a cheap, efficient, and effective means of ruling out a pancreatic cause for hyperamylasemia. It is probable that in the majority of cases of persistent hyperamylasemia without obvious clinical cause there will be no disease at all.
mesh_terms: D000681:Amylases / Q000032:analysis / Q000097:blood*; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D010182:Pancreatic Diseases / Q000201:enzymology* / Q000473:pathology; D010192:Pancreatic Pseudocyst / Q000201:enzymology; D010195:Pancreatitis / Q000201:enzymology; D012463:Saliva / Q000201:enzymology
chemical_list: D007527:Isoenzymes; D000681:Amylases