Diagnostic tests for acute pancreatitis.

Serum amylase continues to be the most widely used test to diagnose acute pancreatitis; however, its popularity does not appear to be justified. The serum amylase test has a poor sensitivity and specificity. Furthermore, it has an extremely low sensitivity in detecting acute alcoholic pancreatitis, which is the most common cause of acute pancreatitis in city hospitals. Older assay techniques for serum lipase were cumbersome and time-consuming. The newer methods seem to have overcome the disadvantages of the previous techniques. They are quick, reliable, and inexpensive. Recent studies indicate that serum lipase may be a better test to diagnose acute pancreatitis. Therefore, serum lipase should be used more frequently in the diagnosis of acute pancreatitis. Serum trypsin, although sensitive, is difficult to estimate and is not routinely available. Serum elastase offers no additional benefit over the serum amylase or lipase tests. Markers such as alpha 2-macroglobulin, RNase, phospholipase, and polymorphonuclear elastase predict severity of disease, but assay techniques for these agents are still experimental and confined to specialized centers. C-reactive protein is a reasonably reliable indicator of severity and, because it is universally available, should be used more frequently. Of the imaging techniques, computerized tomography scanning is the best method to delineate the pancreas; however, ultrasound is more cost-effective in clinical practice.