Pancreatic function testing in cystic fibrosis.

None of the currently available clinical techniques for measuring pancreatic function in patients with CF can be considered "ideal". The "direct" pancreatic stimulation test provides the most information and remains the only truly accurate test of exocrine function, particularly in those individuals with pancreatic sufficiency. The invasive, complex nature of the pancreatic stimulation tests precludes its use as a routine method of assessing pancreatic function in all patients and limits its value for monitoring function in those individuals who are expected to deteriorate with time. Many of the indirect tests of pancreatic function are of value for identifying CF patients with complete pancreatic insufficiency who may require therapy with pancreatic enzyme supplements and fat soluble vitamins. However, none of the currently available "indirect" tests of exocrine function are sensitive enough to evaluate or monitor CF patients with pancreatic sufficiency. Blood tests, capable of measuring pancreatic enzymes in the circulation, such as immunoreactive trypsinogen, may be of value for monitoring pancreatic function in patients with CF, but further longitudinal studies are necessary to fully evaluate this approach. More sophisticated "indirect" tests of exocrine pancreatic function are vitally needed to facilitate adequate assessment of this important digestive organ in patients with cystic fibrosis.