Bilirubin is made up of the residue that is left behind as red blood cells die off at the end of their natural three-month life cycle. The liver is responsible for processing this residue, which is called heme, and passing it along into to your dog’s bile. The resulting bilirubin enters the bloodstream, and is filtered through the kidneys and exits your dog’s body when he urinates or defecates. Direct bilirubin is that which is found in your dog’s urine. Abnormally high levels of bilirubin in your dog’s blood or urine are indicative of illness.
Interpreting Bilirubin Values
While it is not normal for healthy cats to pass bilirubin in their urine, minimal amounts of bilirubin may be detected in the urine of healthy dogs. The normal reference range for the bilirubin level in a dog’s urine is indicated as negative to 1+. If your dog has an abnormally elevated bilirubin level, your veterinarian will want to investigate further to rule out liver disease, gallbladder disease or any conditions that result in excessive red blood cell destruction. Some conditions that can result in a high bilirubin level include toxicity, autoimmune diseases, infectious canine hepatitis, pancreatitis, obstruction of a bile duct, blood parasite infections and some cancers. High bilirubin levels may present as jaundiced, or yellow, coloring that is noticeable on the whites of your dog’s eyes or the skin on the inside surface of your dog’s ears.