Diagnostic value of measuring pancreatic isoamylase with a double-monoclonal antibody immunoassay in serum of hospitalized hyperamylasemic patients.

We evaluated the diagnostic utility of measuring pancreatic isoamylase (P-AMY) with a double-monoclonal antibody technique in a population of 43 consecutive hospitalized hyperamylasemic patients in comparison with serum pancreatic lipase (LPS) activity. In 27 cases (62.8%), the final diagnosis was acute pancreatitis. Predictive values were calculated for P-AMY and LPS activities, and a P-AMY percentage was calculated for selected decision levels. The maximal diagnostic efficiency was 0.930, 0.814, and 0.767 for LPS, P-AMY activity, and P-AMY percentage, respectively, indicating that serum LPS measurement was clinically superior to P-AMY for distinguishing patients with or without pancreatitis. Measurement of both P-AMY activity and percentage in serum did not significantly improve diagnostic accuracy.