[Misleadingly high amylase and pancreatic amylase activity in the plasma of patients with macroamylasemia].
A man aged 68 years with choledocholithiasis and cholangitis, with no clinical signs suggestive of acute pancreatitis and with a low excretion of amylase in the urine, showed persistent hyperamylasaemia which appeared to be caused by macroamylasaemia. The macroamylase (an IgA-lambda-amylase complex) accounted for nearly all (90%) of the amylase activity in the serum. The activity of pancreatic amylase in serum, determined by an immunoinhibition test which selectively blocks salivary amylase activity, constituted 99% of the amylase activity in serum (normal reference range 19-71). We showed, however, that complexed salivary amylase is not inhibited in the test, resulting in a falsely-increased activity of pancreatic amylase in serum. We conclude that macroamylasaemia can lead to a clinically misleading increase in the activity of pancreatic amylase in serum.
Backer
E T
ET
Klinisch Chemisch Laboratorium, Diaconessenhuis, Leiden.
Holtzer
J D
JD
D000368:Aged; D000681:Amylases / Q000097:blood* / Q000652:urine; D002761:Cholangitis / Q000201:enzymology; D002769:Cholelithiasis / Q000201:enzymology; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D046911:Macromolecular Substances; D008297:Male; D010195:Pancreatitis / Q000175:diagnosis / Q000201:enzymology
D046911:Macromolecular Substances; D000681:Amylases; C001663:macroamylase
Misleidende hoge amylase- en pancreasamylase-activiteit in het serum van een patiënt met macro-amylasemie.