FECAL IMMUNOREACTIVE LIPASE - A SIMPLE DIAGNOSTIC-TEST FOR CYSTIC-FIBROSIS

The study evaluates faecal immunoreactive lipase (IRL) measurement in spot stool samples as an index of exocrine pancreatic function in pati ents with cystic fibrosis (CF). Stool samples (211) from 183 healthy v olunteers (age range: 2 days-14.2 years) showed a normal log distribut ion of IRL values with a median concentration of 71.4 mu g/g (range: 0 .53-4160 mu g/g). In 156 stool samples from 58 patients with proven CF , the median IRL concentration of 0.4 mu g/g (range: 0.003-107 mu g/g) was significantly lower (P < 0.001) than that of normal controls. In healthy controls, IRL levels were age related with significantly highe r levels (P < 0.001) shortly after birth compared to older children. S timulation of the exocrine pancreas by oral milk feeding resulted in a significant (P < 0.001) increase in a faecal IRL concentration. Faeca l IRL concentrations in meconium were very low and of the same magnitu de as in patients with CF.Conclusion Faecal IRL determination had a hi gh diagnostic sensitivity (87%) and excellent diagnostic specificity ( 97%) in patients with CF. A negative test result (PVneg: 99%) virtuall y excluded CF under screening conditions.