[Comparison of faecal lipase test and faecal elastase-1 test in the assessment of exocrine pancreatic function in cystic fibrosis].

Objective: In pediatric patients, indirect tests are preferred because of their less invasive character. Among those, faecal elastase-1 test has so far been shown been shown to have the highest sensitivity and specificity. However, the role of the faecal lipase test in the diagnostic work up for pancreatic insufficiency in cystic fibrosis (CF) patients has not been defined. Therefore, the aim of the present study was to compare the sensitivity and the specificity of faecal lipase test to the faecal elastase-1 test in the assessment of exocrine pancreatic function.

Material And Methods: 63 CF patients and 95 healthy subjects (HS) were evaluated. In all subjects, faecal elastase-1 concentration (ELISA) and lipase activity (ELISA) were measured. In 50 HS, sample-to-sample (n=3) variation from the same stool and day-to-day variation from three consecutive stools were determined twice. The presence of pancreatic insufficiency patients was documented in 55 pancreatic insufficient CF patients by the determination of faecal fat excretion and in 12 pancreatic sufficient patients by the direct test. The sensitivity and specificity of the faecal elastase-1 test and faecal lipase test were compared.

Results: The sample-to-sample variation (mean + SEM: 13.2+1.2% vs. 23.4+2.2%) and day-to-day variation (mean + SEM: 16.3+1.2% vs. 32.5+2.6%) were significantly lower (p<0.0001) for elastase-1 determinations than for lipase measurements. With the cut-off levels giving the same specificity for both tests (95.8%), the sensitivity of faecal elastase-1 test (87.3%) was significantly higher (p<0.04) than that of faecal lipase test (77.8%).

In Conclusion: Faecal lipase test is less useful in the assessment of exocrine pancreatic function sensitive than faecal elastase-1 test.