Serum tests for pancreatitis in patients with abdominal pain.

Though the serum total amylase test has been used for the diagnosis of pancreatitis for over 50 years, both its clinical sensitivity and specificity are far from perfect. We first present the results of serial serum total amylase, pancreatic isoamylase, lipase, and immunoreactive trypsin tests in nine patients during the week after their admission to the hospital with a diagnosis of acute pancreatitis, and then compare the serum total amylase, lipase, and immunoreactive trypsin levels in the initial serum submitted for amylase analysis from 100 patients because of the clinical suspicion of acute pancreatitis. In the former group of patients, the serum total amylase test was the least sensitive of the tests for pancreatitis after the first hospital day. In the latter group of patients, the largest discordance was found in patients with elevated serum total amylase levels, but normal lipase and immunoreactive trypsin levels. In 90% of these discordant cases, the elevation of serum total amylase was due to salivary amylase, yielding a maximum clinical specificity of only 71% for serum total amylase. Based on these data, we conclude that alternate tests deserve careful consideration as replacements for the serum total amylase test.