Two indirect tests of exocrine pancreatic function evaluated.

We describe and evaluate two frequently used indirect methods for assessing exocrine pancreatic function: the N-benzoyl-L-tyrosyl-p-aminobenzoic acid test (NBT-PABA) and the pancreolauryl test. In both procedures, the patient is orally administered a substrate that is metabolized into two or more products by pancreatic enzymes. At least one of the reaction products is absorbed from the gut, conjugated, and excreted in urine, where it can be measured. Both tests can be used in the diagnosis and monitoring of cystic fibrosis, chronic pancreatitis, and pancreatic carcinoma, and in monitoring pancreatic enzyme replacement therapy to determine the appropriate dose. In comparison with the NBT-PABA procedure, the pancreolauryl test seems to have better specificity and sensitivity, undergoes almost no interference from other drugs or serum compounds, requires no complex hydrolytic conditions, and is independent of renal function.