Trypsin-like immunoreactivity (TLI)

Trypsin-like immunoreactivity (TLI)

Species: Canine

Specimen: Serum

Container: Red top tube or gel serum tube

Collection protocol: Fasted sample required. Post prandial samples may have elevated TLI values.

Special handling/shipping requirements: Standard

General information about the disease: Exocrine pancreatic insufficiency (EPI) is typically diagnosed once 90% of exocrine function has been lost. Causes of EPI in dogs include pancreatic acinar atrophy, which is an immune-mediated disease most often seen in young adult German Shepherds as well as some Rough Collies and English Setters. EPI may also occur with chronic pancreatitis and with pancreatic tumours.

General information about when this test is indicated: TLI is an accurate and specific indicator of pancreatic function and the test of choice for dogs with EPI. The assay is species specific and measures both trypsin and trypsinogen. Clinical findings with EPI are characterised by fat malabsorption and include weight loss with fatty, foul smelling faeces (steatorrhea) and polyphagia. Hypoproteinaemia is not typically associated with EPI.

Comparison with other related tests:

Plasma lipase is often normal in these cases due to extra pancreatic sources.

Feline EPI is uncommon, however feline TLI can be requested, and is referred overseas to Texas A&M University.


A diagnosis of EPI is supported with very low levels of TLI (<2.5 ug/L).

  • Increased TLI values may also occur with active pancreatitis, marked reductions in glomerular filtration rate.
  • The assay does not cross react with pancreatic enzyme supplementation.