Trypsin-like Immunoreactivity Levels In Your Dog And Cat = cTLI and fTLI

Ron Hines DVM PhD

To see what normal blood and urine values are, go here

For an explanation of causes of most abnormal blood and urine tests, go here

To see how tests are grouped, go here

Canine or Feline Trypsin-like Immunoreactivity In Your Pet’s Blood

Just like the fPL and the cPL tests offered by Idexx laboratories, the TLI test is designed to detect abnormal leakage of digestive enzymes from your dog or cat’s pancreas into the pet’s blood stream – or the lack of the enzymes trypsin and its predecessor (trypsinogen) when the pancreas fails. 

In dogs and cats, elevated results of any of the three of these tests are commonly associated with acute pancreatic problems (=acute pancreatitis) and lowered than normal digestive enzyme levels to pets with chronic pancreatic problems (EPI). Your dog or cat requires those enzymes to properly digest proteins fats and carbohydrates. When there is an insufficient amount of these pancreatic enzymes you pet cannot absorb nutrients adequately. That can cause weight loss, scruffy hair coat, flatulence, a tendency to stool eating (coprophagia), diarrhea or abnormal stool consistency – even if your pet’s appetite remains normal or even increases.

Abnormal TLI levels either way usually point toward the pancreas as the source of problems.

Reasons Your Dog And Cat’s TLI Levels Could Be Low:

Chronic inflammation and subsequent scarring of the portion of your dog or cat’s pancreas that produces digestive enzymes (EPI). The portion of the pancreas that should be producing these enzymes is the exocrine portion

Cats with inflammatory bowel disease (IBD) can have this problem as part of their syndrome. Read about IBD in cats here. Dogs with IBD, are less likely to have their TLI levels affected. You can read about IBD in dogs here .

Cats with triad disease/cholangiohepatitis often have pancreatic problems as part of their disease syndrome – so their TLI tests can also be below (or above) normal depending on what stage of the disease they are in. 

Pancreatic tumors are less common but possible cause.

Some dogs develop antibodies that are directed against their own pancreas (PAA, an autoimmune disease). Those pets may lose their ability to produce pancreatic trypsin. (ref)

Occasionally, TLI levels will be abnormally low (or high) in cats ill due to non-pancreatic issues. I cannot tell you why other than that many disease that caused generalized inflammation affect the entire body. 

Reasons Your Dog And Cat’s TLI Levels Could Be High:

Acute or chronic pancreatitis in dogs and cats, inflammatory bowel disease (IBD), Triad disease and cholangiohepatitis in cats, failing kidneys, malnutrition in dogs, pancreatic hypertrophy in cats. (notice that some of these diseases can make TLI levels go up or down).

Complementary Tests:

Serum amylase and lipase, fPL and cPL tests, repeat the pet’s  TLI  in one month, abdominal ultrasound, blood cobalamin and folate levels, pancreatic biopsy, a normal TLI does not entirely rule out pancreatic problems in your pet

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