[Fecal chymotrypsin concentration in childhood. Normal values, specificity, sensitivity].

The determination of fecal chymotrypsin is a suitable noninvasive screening test for the evaluation of exocrine pancreatic function. Using a photometric assay we found a specificity of 87.5% and a sensitivity of 80%. Beyond the first year of life the lowest limit of normal values is 72 micrograms chymotrypsin/g stool. The method is reproducible, and a 72-hour stool collection is unnecessary when several fecal chymotrypsin determinations in spot stool samples are performed.