This test is usually ordered when someone has symptoms of liver disease such as jaundice, dark colored urine, nausea, abdominal pain or fatigue. Measuring both total and direct bilirubin can help a person’s doctor to differentiate between different types of liver disorders.
Two forms of bilirubin are measured by this tests
- Unconjugated bilirubin—when heme is released from hemoglobin, it is converted to unconjugated bilirubin. It is carried by proteins to the liver. Small amounts may be present in the blood.
- Conjugated bilirubin—formed in the liver when sugars are attached (conjugated) to bilirubin. It enters the bile and passes from the liver to the small intestines and is eventually eliminated in the stool. Normally, no conjugated bilirubin is present in the blood