Ethnie ‘hyperamylasaemia’: clarification by isoamylase analysis

Abstract

Total serum amylase and its pancreatic (P-type) and salivary (S-type) isoamylase activities were measured in 92 individuals without pancreatic or salivary disease. They were divided into three ethnic sub-groups resident in the UK, namely native Britons, Asians and West Indians. The mean total amylase activity was highest in West Indians (383 U/l), intermediate in Asians (317 U/l) and lowest in Britons (179 U/l). Nine of the 28 Asians and 8 of the 16 West Indians had total amylase activities above the upper end of the reference range for Britons. Such a finding, if accompanied by abdominal symptoms, could lead to exhaustive pancreatic investigation in these ethnic groups unless the appropriate reference range is used. Isoenzyme analysis by inhibitor and electrophoretic techniques indicated that the increase in total amylase was due to increase in S-type isoamylase, P-type isoamylase or both. There was a good correlation between results by the two methods. These differences in serum amylase seem to be genetically determined.