Background & Aims: Pancreatic Elastase–1 (EL-1) is a human specific protease enzyme, produced and secreted by pancreatic acinar cells. This enzyme is stable and is not affected by prescriptions of supplement pancreatic enzymes, and it has good connection with pancreatic stimulation function tests. The Purpose of this study is to compare fecal pancreatic elastase–1 concentration in patients with Cystic Fibrosis (CF) and pancreatic insufficiency with the patients without Pancreatic Insufficiency and control group.

Materials & Methods: In this case-control study, 49 persons in 3 groups including control (30 patients), CF without pancreatic insufficiency (8 patients) and CF with pancreatic insufficiency (11 patients) were studied in Tehran Medical Center for Children in 2005. sweat CF was proved with using medical and laboratorial criteria (minimum 2 tests for sweat chloride concentration more than 60 m mole / liter), and the pancreatic function of the patients has been determined by clinical and laboratory methods. Then Fecal Pancreatic elastase–1 and trypsin were measured.

Results: Average concentration of fecal pancreatic elastase–1 in patients with CF and pancreatic insufficiency was significantly lower than 2 other groups. But there were no significant differences between the control group and the patients with CF and without pancreatic insufficiency. The best discrimination level of fecal pancreatic elastase–1 for dividing patients into two groups including patients with and without pancreatic insufficiency is 96.5µg/g. With this level , sensitivity of this test will be 100% (at 95% confidence level, from 90.82% to 100%) specificity of this test 81.82% (at 95% confidence level, from 52.30% to 94.86%) and accuracy of this test 95.92% (at 95% confidence level, from 87.16% to 98.79%). Decrease in Trypsin among the patients with CF and pancreatic insufficiency is significantly higher than thecontrol group and the patients with CF and without pancreatic insufficiency (100% against 50% and 37.50%, P=0.004). therefore, the sensitivity of this test will be 52.63% (at 95% confidence level, from 37.26% to 67.52%) specificity of this test 100% (at 95% confidence level, from 74.12% to 100%) and accuracy of this test 63.27% (at 95% confidence level, from 51.61% to 74.32%). Sensitivity and accuracy of the test for fecal pancreatic elastase–1 is significantly higher than fecal trypsin (P<0.001), but specificity of trypsin is significantly higher than fecal pancreatic elastase–1 (p<0.005).

Conclusion: Fecal pancreatic elastase–1 concentration in patients with CF and pancreatic insufficiency is significantly lower than control group and patients with CF and without pancreatic insufficiency. Sensitivity and accuracy of this test is significantly higher than Trypsin.