Diagnosis of acute pancreatitis: a proposed sequence of biochemical investigations.

In 60 controls and 108 patients admitted with acute abdominal pain, Rapignost urinary amylase correctly identified (++) 18 of the 23 patients with acute pancreatitis (AP), with 8 results being equivocal (+), and 1 false negative. This is a suitable screening test for AP, but an equivocal result requires further investigation. In 14 patients with AP the serum amylase was over 1000 U/l with no false-positive results, whereas when 316 U/l was used as the diagnostic threshold, 22 cases were identified (but with 2 false positives). Serum lipase was 100% sensitive in the diagnosis of AP, but there were three false-positive results.