FrançaisWhat bile acids show
The liver makes bile acids, stores them in the gall bladder and releases them into the gut after a meal. They are reabsorbed into the blood that flows from the gut to the liver, and a healthy liver removes almost all of them on the first pass [1].
Bile acids rise in the blood when the liver has lost functional mass, when blood bypasses the liver (portosystemic shunt or portal vein hypoplasia), or when bile flow is blocked (cholestasis) [1]. That is why vets use the test when liver enzymes are abnormal, or in young dogs with signs that suggest a shunt.
How the test is done
- Fasting sample: after an overnight fast, or just before the usual morning meal [1].
- Meal: your dog eats its regular food, in its usual amount, to make the gall bladder contract [1].
- Post-meal sample: 2 hours after eating [1].
- Puppies: in breeds prone to congenital shunts, testing is recommended after 16 weeks of age, as younger puppies can have falsely low values [1].
The two-sample panel is preferred because the meal “challenges” the liver and makes the test more sensitive [1].
How to read the bile acids results
Here is an example of the two lines.
- Abbreviation BA, SBA or bile acids, often reported as “pre” (fasting) and “post” (2 hours).
- Result 68 µmol/L in this illustrative line, after the meal.
- Unit µmol/L in most laboratories.
- Laboratory interval Each laboratory sets its own limit. Cornell considers values above 25–30 µmol/L in dogs suggestive of liver disease [1].
- Flag H: above the limit. The higher of the two samples is the one that counts [1].
Interpreting the numbers
| Result (dogs) | What it usually means |
|---|---|
| Both samples below 15 µmol/L | Liver disease unlikely [1]. |
| 15–25 µmol/L | Equivocal: read with the rest of the work-up [1]. |
| Above 25–30 µmol/L | Suggests reduced liver function, a shunt or cholestasis [1]. |
| Markedly high, especially after the meal | Typical of a portosystemic shunt [1, 2]. |
In a German study of 373 dogs, bile acids above the laboratory limit picked up 93% of dogs with a portosystemic shunt, but were also high in about a third of dogs without a shunt: the test points to a problem, imaging confirms a shunt [2].
Up to 20% of dogs have a fasting value higher than the post-meal value, because of a recent meal, gall bladder contraction during the fast or slow stomach emptying. The higher value is used [1].
What can make the result unreliable
- High bilirubin or jaundice from cholestasis. Bile acids will be high anyway, so the test adds no information about liver function [1].
- Lipemia and hemolysis. With older methods, fat in the sample can raise the result and broken red cells can lower it [1].
- Slow digestion. Poor absorption, fast transit or delayed stomach emptying can lower the values and hide a problem [1].
- Other conditions. Dogs with Cushing’s syndrome, and some with dental disease, can have high bile acids without primary liver disease [1].
Results often read with bile acids
A low blood sugar in a young toy-breed dog is discussed in blood sugar in dogs.
When bile acids are very high in a young dog: liver shunt in dogs.
En français : acides biliaires chez le chien.
Questions to ask your veterinarian
- Why are you recommending a bile acids test rather than repeating the liver enzymes?
- Should my dog fast, and what should I feed for the post-meal sample?
- Which of the two values counts, and what is your laboratory’s cut-off?
- Could a shunt explain the result, and what would confirm it?
- Is bilirubin normal, so that the test is interpretable?
Get your dog’s liver results explained together.
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Frequently asked questions
What is a normal bile acid level in a dog?
Laboratories set their own limits. Cornell considers values below 15 µmol/L on both samples reassuring and values above 25–30 µmol/L suggestive of liver disease [1].
What causes high bile acids in dogs?
Reduced liver function, blood bypassing the liver through a shunt, or blocked bile flow. Cushing’s syndrome and dental disease can raise them too [1].
When should a bile acids test be performed?
When liver enzymes are abnormal and your vet wants to check liver function, or when a young dog shows signs that suggest a shunt, after 16 weeks of age in predisposed breeds [1].
Does my dog need to fast for a bile acids test?
Usually yes for the first sample, then a normal meal and a second sample 2 hours later. Follow your vet’s instructions [1].
Why is the fasting value higher than the after-meal value?
It happens in up to 20% of dogs, for example after gall bladder contraction during the fast. The higher value is the one interpreted [1].
Sources
- eClinPath, Cornell University College of Veterinary Medicine. Bile acids. eclinpath.com/chemistry/liver/liver-function-tests/bile-acids
- Ruland K, Fischer A, Hartmann K. Sensitivity and specificity of fasting ammonia and serum bile acids in the diagnosis of portosystemic shunts in dogs and cats. Vet Clin Pathol. 2010;39(1):57-64. doi.org/10.1111/j.1939-165X.2009.00178.x
Laboratory methods and reference intervals vary. This article explains; it does not diagnose. For a decision about your pet, use the original report and talk to your veterinarian. Our editorial policy.