Studies of urine bile acids in people have shown them to be a sensitive test for liver dysfunction.

There are several advantages of urine bile acids over serum bile acids measurement:

• no requirement for fasting.
• avoids shortcomings of randomly collected serum samples and spurious results caused by spontaneous gall bladder contraction, incomplete or delayed gastric emptying, and slow intestinal transit time.
• provides a time-averaged sample that dampens acute changes in serum bile acids concentration that can occur due to physiologic variables affecting the enterohepatic circulation.
• no need for multiple venipuntures.
• less costly to perform.

Recent studies have evaluated urine bile acids testing in dogs and cats with liver disease. Serum and urine bile acids concentrations were compared in 126 dogs and 79 cats. Of the dogs, 102 had liver disease diagnosed at biopsy, 9 had other diseases, and 15 were healthy. Of the cats, 54 had liver disease, 17 had other diseases, and 8 were healthy. The highest serum bile acids concentration from either fasting, post-prandial, or randomly taken samples was compared to the urine bile acids concentration, collected within 24 hours of the serum. Urine bile acids concentrations were reported as a ratio to urine creatinine to eliminate changes due to differences in urine flow and urine concentration.

Results:

• for dogs, the sensitivity and specificity of urine bile acids for diagnosis of liver dysfunction were 61% and 100%, respectively, whereas serum bile acids had a sensitivity of 78% and specificity of 67%.
• for cats, the sensitivity and specificity of urine bile acids were 85% and 88%, respectively, whereas serum bile acids had a sensitivity of 87%, and the same specificity of 88%.
• patients with porto-systemic shunts (PSS) tended to have lower urine bile acids: creatinine ratios than patients with hepatocellular disease.

• the sensitivity and specificity of urine bile acids measurement were similar to those of serum bile acids, but the urine bile acids test was more specific for canine liver dysfunction than was serum bile acids testing.
• a pattern of results showing very high serum bile acids but only slightly increased urine bile acids may be indicative of a shunting disease such as PSS or MVD.
• while bile acids testing can identify animals with hepatic dysfunction, it may fail to recognize animals with hepatic disease in the absence of hepatic dysfunction.

To Measure Urine Bile Acids, 1mL of urine is required. Test Code 85645.

A randomly collected urine sample is acceptable, but blood contamination should be avoided.