Faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis.

BACKGROUND AND AIMS: Direct tests are characterized by the highest sensitivity and specificity. However, their practical use, especially in children, is limited. Among the indirect tests, the highest sensitivity and specificity was documented for faecal elastase-1 test, yet the value of faecal lipase test in cystic fibrosis (CF) has not been defined. Therefore, the aim of the present study was to compare the sensitivity and the specificity of the faecal lipase test to the faecal elastase-1 test in the assessment of exocrine pancreatic function in children with CF.

METHODS: The study comprised 90 CF patients and 95 healthy subjects (HS). In all subjects, faecal elastase-1 concentrations (ELISA) and lipase activities (ELISA) were measured. The presence of pancreatic insufficiency was documented by the determination of faecal fat excretion in 78 pancreatic insufficient and by the secretin-cholecystokinin test in 12 CF patients without steatorrhoea. Sensitivity and specificity of the faecal elastase-1 test and faecal lipase test were analysed and, in 50 HS, sample-to-sample and day-to-day variations were determined.

RESULTS: With cut-off levels providing the same specificity for both tests (95.8%), the sensitivity of the faecal elastase-1 test (91.1%) was significantly higher (p < 0.0036) than that of the faecal lipase test (76.7%). Sample-to-sample (mean +/- SEM: 13.2 +/- 1.2% vs 23.4 +/- 2.2%) and day-to-day variations (mean +/- SEM: 16.3 +/- 1.2% vs 32.5 +/- 2.6%) were significantly lower (p < 0.0001) for elastase-1 than for lipase measurements.

CONCLUSION: Among indirect tests, faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis.