RESUMO
UNLABELLED: The study evaluates faecal immunoreactive lipase (IRL) measurement in spot stool samples as an index of exocrine pancreatic function in patients with cystic fibrosis (CF). Stool samples (211) from 183 healthy volunteers (age range: 2 days-14.2 years) showed a normal log distribution of IRL values with a median concentration of 71.4 micrograms/g (range: 0.53-4160 micrograms/g). In 156 stool samples from 58 patients with proven CF, the median IRL concentration of 0.4 microgram/g (range: 0.003-107 micrograms/g) was significantly lower (P < 0.001) than that of normal controls. In healthy controls, IRL levels were age related with significantly higher levels (P < 0.001) shortly after birth compared to older children. Stimulation of the exocrine pancreas by oral milk feeding resulted in a significant (P < 0.001) increase in a faecal IRL concentration. Faecal IRL concentrations in meconium were very low and of the same magnitude as in patients with CF. CONCLUSION: Faecal IRL determination had a high diagnostic sensitivity (87%) and excellent diagnostic specificity (97%) in patients with CF. A negative test result (PVneg. 99%) virtually excluded CF under screening conditions.