Abstract

Serum bile acid concentrations have been measured in domestic and captive wild animals as an ancillary test to diagnose and monitor the progression of liver disease. Bile acid tests are a measure of liver function, while elevations of liver enzyme concentrations represent hepatocyte damage or cholestatic disease. Urinary concentrations of sulfated and nonsulfated bile acids have been shown to be significantly higher in domestic cats with liver disease than in cats without liver disease.¹ The specificity and sensitivity of urinary bile acid measurement for liver disease diagnosis are similar to that of serum bile acid measurement in domestic cats. Urinary bile acids are compared to urinary creatinine concentrations (urine bile acid to urine creatinine ratio) to allow interpretation of urine collected at arbitrary times. The advantages of urinary bile acid measurement include no requirement for venipuncture, a time-averaged sample that lessens the effects of daily physiologic variation, and a completely non-invasive procedure.

Upon incidental discovery of elevated liver enzyme concentrations and serum bile acid concentrations in a white Bengal tiger (Panthera tigris tigris), serial urinary bile acid tests were used to evaluate and monitor liver function while avoiding repeated anesthetic procedures for venipuncture. The urine bile acid to urine creatinine ratio is a non-species-specific, non-invasive, clinically significant laboratory test that can help to diagnose and monitor liver disease in captive exotic felines.

Literature Cited

1.  Trainor D, Center SA, Randolph JF, Balkman CE, Warner KL, Crawford MA, et al. Urine sulfated and nonsulfated bile acids as a diagnostic test for liver disease in cats. J Vet Intern Med. 2003;17:145–53.