Fecal immunoreactive elastase 1: A new tubeless pancreatic function test.

Aim. - The aim of this study was to evaluate the potential and precision of the fecal elastase type 1 test in comparison to the secretin-pancreozymin-test in the diagnosis of exocrine pancreatic insufficiency. Methods. - We studied 254 stool samples from 102 individuals without malabsorption (n=53) and patients with pancreatic maldigestion syndromes (n=49). Pancreatic elastase was measured immunologically, using a new enzyme immunoassay according to the sandwich technique. Results. - Spot stool immunoreactive elastase activity in controls ranged from 136 to 4,400 mu g/g. Ninety five percent of all values where within 175 to 1,500 mu g/g. The lower limit of normal was defined as 150 mu g/g. No significant decrease of immunoreactivity was found when stool samples were stored at room temperature over five days. The assay variability calculated from 10 consecutive assays of a single fecal sample gave coefficients of variation ranging from 3.3 to 6.3% for intraasay-variability and from 4.1 to 10.2% for interassay-variability. There was a good correlation between the output of elastase compared to lipase output with correlations coefficients of 0.821 in controls and 0.905 in patients with impaired pancreatic function. In stool samples of 49 patients with exocrine pancreatic insufficiency the concentration of fecal elastase was significantly lower (P < 0.001) compared to controls and patients with Crohn or coeliac disease. Elastase immuno-reactivity showed higher sensitivity and specificity as compared to fecal chymotrypsin. Furthermore, in contrast to fecal chymotrypsin, the test results were unaffected by pancreatic enzyme replacement therapy. Conclusion. - These results indicate that fecal immunoreactive elastase may be recommended as a new, non-invasive easy-to-perform tubeless pancreatic function test with a high sensitivity and specificity in comparison with healthy controls.