To compare the clinical utility of serum pancreas-specific protein and serum amylase in the diagnosis of acute pancreatitis, the study was conducted in 134 normal subjects and 70 patients (36 with acute pancreatitis and 34 with other acute abdominal diseases as control group). The serum level of pancreas-specific protein in 134 healthy adults was 29.6 +/- 1.6 micrograms/l, with 95% within 7.3-67.2 micrograms/l. The upper reference limit was set at 70 micrograms/l. Serum levels of pancreas-specific protein and amylase within 12 h of arrival were significantly higher in patients with acute pancreatitis than in the control group (647.3 +/- 79.3 versus 33.8 +/- 4.8 micrograms/l (p < 0.0001) and 2536 +/- 344 versus 175 +/- 35 IU/l (p < 0.0001)). No significant difference in the levels of pancreas-specific protein was noted between biliary and alcoholic pancreatitis or between severe and mild attacks. The sensitivity, specificity, and accuracy of diagnosing acute pancreatitis were 100%, 94.1%, and 97.1% with serum pancreas-specific protein > 70 micrograms/l and 97.2%, 91.2%, and 94.3% with serum amylase > 360 IU/l. The result demonstrated that pancreas-specific protein may be a good serum marker in the diagnosis of acute pancreatitis.