Serum immunoreactive trypsin, pancreatic polypeptide, and pancreatic isoamylase as diagnostic tests for chronic pancreatitis.

The efficiency of immunoreactive trypsin (IRT), pancreatic polypeptide (PP), and pancreatic isoamylase (PI) in the diagnosis of chronic pancreatitis was studied in 80 consecutive patients clinically suspected of having chronic pancreatitis. Twenty-five patients had chronic pancreatitis, and of these, 17 had pancreatic insufficiency. IRT, PP, and PI were of no value in the diagnosis of chronic pancreatitis without insufficiency. The three tests were of equal but limited value in diagnosing pancreatic insufficiency (nosographic sensitivities, 0.53 to 0.59, and predictive values of a negative test, 0.88 to 0.90). The combination of IRT, PP, and PI did not increase the diagnostic efficiency compared with each of the three tests alone. We conclude that IRT, PP, and PI are of similar but limited value as diagnostic tests for pancreatic insufficiency.