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1390 Trypsin-Like Immunoreactivity (TLI) Urinalysis

Specimen Collection and Handling Relative Cost: $$ evaluation is required to determine the underly-
Serum (red top tube), heparinized plasma (green Pearls ing cause.
VetBooks.ir refrigerate or freeze at −20°C. Elevated cardiac troponin indicates myocardial AUTHOR: Ruanna E. Gossett, DVM, PhD, DACVP
top tube), or EDTA plasma (lavender top tube);
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
injury, but not etiologically specific. Further

Trypsin-Like Immunoreactivity (TLI)

Definition TLI is not recommended for diagnosis of Lab Artifacts
Species-specific immunologic assay used to pancreatitis; species-specific pancreatic lipase High temperatures will cause artifactual decrease
diagnose exocrine pancreatic insufficiency (EPI) (PLI) assay is the preferred test. in TLI.
• Evaluate for pancreatitis (e.g., PLI; see pp.
Synonyms 740, 742, and 1370). Specimen Collection and Handling
TLI, fTLI (feline specific), cTLI (canine • Evaluate for decreased GFR. Serum (red top tube), nonhemolyzed, fasting
specific) (12-18 hours) sample
Causes of Abnormally Low Levels
Physiology Exocrine pancreatic insufficiency (EPI) Relative Cost: $$
The assay detects trypsinogen, trypsin, and
trypsin bound to a proteinase inhibitor. Next Diagnostic Steps to Consider Pearls
Trypsinogen, the inactive form of trypsin, if Levels are Low • Ensure that species-specific assays are
is produced by pancreatic acinar epithelial Results < 2.5 mcg/L (dogs) and < 8 mcg/L performed.
cells and is present in low concentrations in (cats) are diagnostic for EPI. • Oral supplementation with pancreatic
the blood of normal patients. EPI leads to • Evaluate serum cobalamin (B 12 ) and folate extracts does not interfere with TLI assays.
reduced amounts of trypsinogen released into (associated abnormalities common).
circulation. • See p. 317. AUTHOR: Carrie L. Flint, DVM, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
Values of 2.5-5 mcg/L (dogs) or 8-12 mcg/L
Reference Interval (cats) are equivocal:
Dogs: 5-45 mcg/L; cats: 12-82 mcg/L • If GFR decreased, low concentration from
EPI may increase into equivocal range.
Causes of Abnormally High Levels • Ensure fasting (12-18 hours) sample.
Pancreatitis, decreased glomerular filtration rate • Repeat TLI assay in 4 weeks.
(GFR), malnourished patients (usually dogs)
Important Interspecies Differences
Next Diagnostic Steps to Consider An association between increased TLI and
if Levels are High cobalamin deficiency can exist in the cat, and
• TLI > 50 mcg/L (dogs) or > 100 mcg/L cobalamin supplementation variably improves
(cats) is consistent with pancreatitis, although TLI results.

Urinalysis

Definition tract is less likely. Physical properties of Reference Interval
The physical, chemical, and microscopic evalu- urine include the evaluation of color, clarity, The following values are observed in healthy
ation of urine and solute concentration (specific gravity). dogs and cats:
Chemical analysis is commonly performed • Color: yellow to amber
Synonym with a urine dipstick (test strip) and includes • Clarity: clear
UA measurements of urine pH, protein, glucose, • Specific gravity: 1.015-1.045 (dog) and
ketones, blood, and bilirubin. Lastly, the 1.035-1.060 (cat)
Physiology urine sediment is examined microscopically • pH: 6.0-7.5
Urine can be collected via the following for the presence of casts, crystals, red blood • Protein, glucose, ketones, blood: negative
techniques: free-catch (voided), table col- cells, white blood cells, epithelial cells, bac- • Bilirubin: Can be low positive in healthy dogs.
lection (i.e., aspirated from clean table or teria, yeast, parasites, lipid, and/or sperm. Any positive result is significant in cats.
floor after voiding), catheterization, and A urinalysis provides insight to the patient’s • Casts: 1-2 hyaline and 0-1 granular
cystocentesis. Submission of urine collected hydration status and renal function as well • Crystals: struvite, calcium oxalate dihydrate,
by cystocentesis is ideal, as contamination as the presence of disease (e.g., protein-losing and brushite crystals can be observed in
from the environment or distal urogenital nephropathy, urinary tract infection). healthy dogs or cats.

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