The Bilirubin blood test aids in the diagnosis of hemolytic anemia, a condition characterized by a lack of red blood cells in blood. This condition may cause a patient to feel lethargic and become pallor. A possible yellowing of the skin and eyes, called jaundice, can be detected by monitoring bilirubin levels.

The level of liver functioning or damage is also determined by the levels of bilirubin found in blood. When any test confirms critical levels of greater than 15 mg/dL, it is crucial to perform further testing to differentiate the cause of abnormally increased levels of bilirubin in blood.