Serum TLI will detect exocrine pancreatic insufficiency (EPI) in dogs and cats in a single blood sample and this remains the test of choice for EPI in both species. Samples must be serum and the animals need to be fasted for at least 6 hours and preferably overnight. Acute pancreatitis gives rise to very high levels due to increased amounts of trypsinogen released into the general circulation. It is very important to sample suspected cases of pancreatitis as early as possible to obtain an accurate diagnosis, as the levels of TLI decrease as the condition progresses.

Interpretation
Animals with EPI have very low levels of TLI. Animals with pancreatitis may have very high levels of TLI.