Can Give ComplementaryClinicalInformation

We report the presence of an extremely high proportion of “aged ” amylase in the serum and cyst fluid of a patient with a pancreatic pseudocyst. A salivary amylase inhibitor test helped us to differentiatethese “aged ” pancreaticamylases from salivary fractions having a similar electrophoretic mobil-ity. AddItIonal Keyphrases: P- and S-type am}dase isoenzymes “aged ” amylases macroamylasemia. amylase electro-phoresis amylase inhibition. pancreatic pseudocysts pancreatitis. monitoringtreatment In the past decade, isoamylase assays have emerged as a useful diagnostic tool in a wide array of clinical situations, particularly in gastroenterology, gynecology, and pediatrics (1-3). This increased popularity was largely catalyzed by the concurrent availability of simplified electrophoretic techniques (1, 2, 4) and spectrophotometric assays that exploit salivary inoamylase-specific inhibitors (5) or precipi-tating antibodies (6). Using such an inhibitor assay, Koehler et al. (7) showed that routine isoamylase determination could change the clinical diagnosis in 20 to 40 % of hypera-mylasemic patients. Some comparative studies have advo-cated the use of inhibitortestsfor clinical routine applica-tions (8,9), but other reportshave documented that electro-phoretic techniques yield more clinicallyusefulinformation, especially in cases of acute pancreatitis (10), pancreatic pseudocysts (11), extrapancreatic tumors (3), and macroa-mylasemia (4). It is the purpose of the present study to reconcile the two opinions by illustrating that the two types of assays are complementary rather than mutually exclusive and hence should be ordered simultaneously in those patients with pancreatic disease or hyperamylasemia, or both, where unambiguous interpretation of isoaniylase patterns is diffi-cult