Comparative study of serum pancreatic isoamylase, lipase, and trypsin-like immunoreactivity in pancreatic disease.

Serum total amylase, pancreatic and salivary isoamylase, lipase and trypsin-like immunoreactivity (TLI) were measured in 16 patients with acute pancreatitis, 37 patients with chronic pancreatitis, 11 patients with pancreatic cancer, and 53 control subjects in order to evaluate the relative value of these tests in the diagnosis of pancreatic disease. In acute pancreatitis patients studied within 2 days from the onset of pain all pancreatic enzymes were abnormally high. In chronic pancreatitis patients serum pancreatic isoamylase and TLI were abnormally low in 8 out of 10 patients with severely impaired pancreatic exocrine function, while lipase was abnormally low in 6 patients. During acute exacerbations of the disease elevated levels of pancreatic isoamylase and lipase, but not of TLI, were found in about one third of cases. In patients with pancreatic cancer the pattern of changes in serum pancreatic enzymes was variable since levels within, below and above the normal range were found. The results demonstrate that in acute pancreatitis all serum pancreatic enzymes had the same diagnostic sensitivity, however serum lipase determination is the most convenient because of its simplicity and low cost. In chronic pancreatitis serum pancreatic isoamylase and TLI may be useful in detecting severe pancreatic insufficiency. In pancreatic cancer serum pancreatic enzymes lack diagnostic specificity.