Abstract. The detection of pancreatic elastase 1 in stool samples has become the noninvasive gold standard for the diagnosis of pancreatic insufficiency in humans. Accordingly, the development of a sandwich-ELISA specific for canine pancreatic elastase 1, based on monoclonal antibodies, is presented here. The test has a detection range of 4-240 g canine pancreatic elastase 1/g feces. The intraassay coefficient of variation is 7.4%, and the interassay coefficient of variation is 7.7%. Spiking experiments show that canine elastase 1 is quantitatively detectable in fecal samples. Interestingly, the range of the elastase 1 concentration in canine feces within several days is higher as compared with humans. As the proposed cutoff of 10 g/g is below this variation range in 96.1% of the tested samples, the effect on the test specificity is negligible. Because the test detects neither human nor bovine and porcine elastase 1, pancreatic function can be monitored without interrupting an enzyme replacement therapy.Clinical signs of weight loss, diarrhea, and polyphagia are leading symptoms for malabsorption, usually caused by small intestinal disease/enteritis, and for maldigestion, caused by exocrine pancreatic insufficiency (EPI). 20 Thus, differential diagnosis of EPI requires an organ-specific diagnostic method. The most common cause for EPI is pancreatic acinar atrophy, followed by occasionally relapsing pancreatitis in elderly dogs, leading to EPI if more than 90% of the pancreatic tissue is destroyed. 15,19,20 Various tests are available for the diagnosis of canine EPI. At present, the most frequently applied test is the detection of canine trypsin-like immunoreactivity (cTLI) in dog's serum with a radioimmunoassay. 21,22 This test is most reliable and delivers usually accurate results. It was particularly developed for the diagnosis of EPI in dogs.All other tests are less reliable in terms of sensitivity and specificity, 11 like an enzyme-linked immunosorbent assay (ELISA) for the detection of cTLI and a test for chymotrypsin activity in feces. 7 Similarly, other noninvasive pancreatic function tests (oral fat absorption test, pancreatic proteolytic enzyme activity test, starch tolerance test, BT PABA-test, xylose absorption test) are often misleading because they produce a high proportion of equivocal results. 1,9,20 Most of these tests (with the exception of the tests for serum canine TLI) were adapted from diagnostic procedures
