In 134 consecutive patients with acute abdominal pain, we evaluated the clinical role of a new rapid test for serum lipase based on latex agglutination. The results were compared with those obtained with a widely used lipase immunoassay as well as with serum amylase and pancreatic isoamylase measurements. Fifty-five healthy subjects were studied as controls. In 174 cases (121 patients and 53 controls) the results of the two lipase assays were in agreement. A positive lipase latex test was found in 10 of 12 patients with acute pancreatitis, in eight of 24 patients with other pancreatic diseases, and in 14 of 98 with nonpancreatic diseases. The sensitivity and specificity of this test were similar to those of the other pancreatic enzyme assays performed. The results indicate that the lipase latex agglutination test is useful for emergency screening for acute pancreatitis in patients with acute abdominal pain.