Abnormal pancreatic electrolyte secretion in cystic fibrosis. Reliability as a diagnostic marker.

We performed pancreatic function tests on sixty-five cystic fibrosis (CF), and eleven control children. The technique used continuous IV infusion of cholecystokinin and secretin, with duodenal juice collection over a 90 min period, and was made quantitative by continuous duodenal infusion and distal collection of an unabsorbable marker (bromosulphthalein). Some CF patients had near normal pancreatic enzyme outputs, some had impaired but measurable levels, but most (79%) had almost absent trypsin secretion. CF children with better pancreatic function, were younger and more likely to be male. All controls showed a large increase in bicarbonate concentration and secretion rate per kilogram body weight during the test, but most children with CF (96.5%) did not. Because two of our CF patients had water and bicarbonate secretion within the control range, this finding does not exclude the diagnosis of CF. Sodium, potassium and chloride ion secretion in CF patients was lower than controls but overlap occurred. We found a linear correlation between acinar and tubular secretion in CF patients which indicates that there is probably not a primary genetic defect in pancreatic bicarbonate secretion in CF.