LaboratoryTests in the DifferentialDiagnosisof Hyperamylasemia

We evaluated the clinicalutilityof some recentlydeveloped laboratorymethods, includingtotal amylase by three meth-ods; isoamylase by inhibitionand isoelectricfocusing;lipase by pH-Stat and turbidimetry; and immunoreactivetrypsin. All methodscorrelated highly positivelywith hyperamylasemia due to primary acute pancreatitis.Pancreatic-typeisoamy-lase determinationshave the greatestclinicalusefulness, because total amylase, lipase, and immunoreactivetrypsin are Increased in a relativelyhighpercentageofotherabdomi-nal diseases. Increases in the last-mentioned enzymes in nonpancreatic abdominal disease may be the result of inju-riesto the pancreassecondary to the primarydisease,which are being detected with these highly sensitive methods. Becauseof the highclinicalsensitivityof lipaseand immuno-reactive trypsin determinations, a normal result tends t