Diagnostic value of measuring pancreatic lipase and the P3 isoform of the pancreatic amylase isoenzyme in serum of hospitalized hyperamylasemic patients.

We assayed amylase (AMY) isoenzymes by cellulose acetate electrophoresis and determined pancreatic lipase (LPS) activity by a turbidimetric colipase-supplemented method in 54 hospitalized hyperamylasemic patients (32 men and 22 women; mean age 61.5, SD 16, years). In AMY isoenzyme analysis, use of a value for P3 isoform greater than 14 U/L as a positive test for acute pancreatitis gave a diagnostic efficiency of 92.6%, a predictive value of a positive test result of 90.5%, and a predictive value of a negative test of 100%. Four of 12 patients with other, nonpancreatic abdominal diseases had false-positive test results. LPS activity (cutoff limit, 700 U/L) was as effective as P3 isoform in distinguishing patients with acute pancreatitis (sensitivity, 100%) from those without acute pancreatitis (specificity, 81.3%). Thus, P3 isoform and LPS appear to be interchangeable markers of pathological release of pancreatic enzymes into the bloodstream during acute pancreatitis. This finding decreases the need for the expensive radiological procedures currently required to confirm this diagnosis. In particular, negative results virtually exclude acute pancreatitis.