What causes high bilirubin levels (hyperbilirubinemia)? Bilirubin might build up in your blood if: Your body breaks down too many red blood cells too fast. You might be overproducing bilirubin if you have a blood disorder, such as hemolytic anemia, that destroys red blood cells. Your liver is struggling to process its normal load of bilirubin.

High or low bilirubin levels might indicate that some part of the process of breaking down and clearing old red blood cells isn’t working correctly. What do bilirubin levels in your blood indicate? Healthcare providers often give bilirubin tests to check on the health of your liver.