Elastase, Serum

The Elastase, Serum test (serum pancreatic elastase-1; serum elastase; pancreatopeptidase) assists in diagnosing acute pancreatitis and in recognizing exacerbations of chronic pancreatitis. It also contributes to the differential diagnosis of epigastric pain and is useful when clinical findings or imaging raise concern for pancreatic inflammation.

Elastases are proteolytic enzymes that degrade multiple substrates, including elastin, casein, fibrin, albumin, denatured hemoglobin, and denatured collagen. In circulation, their activity is curtailed by protease inhibitors such as alpha-2-macroglobulin, antithrombin III, alpha-1 antitrypsin, alpha-1 chymotrypsin, and beta-1 anticollegenase. Two principal isoforms are recognized: pancreatic elastase-1, produced by the exocrine pancreas, and neutrophil (leukocyte) elastase, stored in azurophilic granules and involved in diverse inflammatory responses. Under normal conditions, pancreatic elastase activity in serum is minimal and is rapidly neutralized by circulating inhibitors. In acute pancreatic inflammation—whether acute pancreatitis or a flare of chronic pancreatitis—serum pancreatic elastase-1 increases early, often within 48 hours, and can precede rises in amylase and lipase. Concentrations may also remain elevated longer than these traditional enzymes, supporting confirmation of a suspected diagnosis. Serum elastase concentrations do not correlate with the anatomic extent of pancreatic necrosis. By contrast, fecal elastase testing evaluates exocrine pancreatic function rather than acute inflammatory activity.