Urine bilirubin
Urine ·Also called: BIL urine, bilirubinuria, urine bile pigment
What it is
Bilirubin comes from the breakdown of red blood cells and is normally excreted in bile. The dog's kidney can process and excrete a little of it directly, which is why traces appear in canine urine without disease. The cat's kidney has a much higher threshold.
Why your vet measures it
Bilirubin often appears in urine before the animal looks jaundiced, so it can be an early flag for liver disease, bile duct obstruction or red cell destruction. In a cat, it should always prompt a look at the liver values.
What a positive result can mean
- Liver disease or reduced bile flow
- Destruction of red blood cells
- Obstruction of the bile duct
- In dogs: concentrated urine, particularly in males, where a trace can be normal
What a negative result means
- A negative result is normal, and is the expected finding in every healthy cat
Dogs and cats differ
This is one of the cleanest dog-versus-cat differences in urinalysis. A one-plus bilirubin in a concentrated canine sample is often ignored; the same result in a cat is treated as a genuine finding and triggers liver testing.
Questions worth asking your vet
- For a cat, do we need to check the liver values because of this?
- How concentrated was the sample?
- Are the gums or eyes showing any yellow tinge?
Related terms
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