Tubeless tests of exocrine pancreatic function in patients with cystic fibrosis

In order to determine the value of non-invasive tests in the analysis of exocrine pancreatic function in cystic fibrosis, 14 older cystic fibrosis patients were studied by a set of non-invasive tests. The tests comprising trypsin, total amylase, pancreatic isoamylase, lipase and pancreatic polypeptide (PP) in fasting serum, PP in postprandial serum, and p-aminobenzoic acid (PABA) excretion in urine, were compared to faecal fat excretion after discontinuation of pancreatic enzyme supplementation. Eleven of the 14 patients were found to have a faecal fat excretion of more than 7 g per day. Serum levels of trypsin, pancreatic isoamylase and lipase and the urinary excretion of PABA showed significant negative correlations with faecal fat excretion. Although serum trypsin, postprandial PP and urinary PABA excretion were the most sensitive tests for severe exocrine pancreatic insufficiency, the differences in sensitivity were rather modest. Therefore, the type of test to be selected for clinical use is mainly dependent upon factors as accessibility, simplicity, patient's acceptability and costs.