Bilirubin (Direct)

If your liver is healthy, it will remove most of the bilirubin from your body through your bile ducts (the tubes that carry bile from your liver). If your liver is damaged or your bile ducts are blocked, bilirubin can leak out of your liver and into your blood. When too much bilirubin gets into the bloodstream, it can cause jaundice, a condition that causes your skin and eyes to turn yellow. If you have jaundice, your health care provider may order a bilirubin blood test to check for liver disease or damage.

Bilirubin is usually tested with a blood test but can also be tested in your urine.

Direct (also called conjugated) bilirubin is the form your liver has already processed and is ready to release into bile. Measuring direct bilirubin separately can help your provider tell apart different kinds of liver and bile-flow problems.

The results will show if the amount of bilirubin in your blood is in the normal range. The normal ranges can vary from lab to lab.

If the results are outside your lab's reference range, you may need further testing. Normal results can vary based on the lab, your sex, and if the test is being done on an infant or child. High bilirubin levels may mean your liver isn't working right.

High bilirubin levels (hyperbilirubinemia) may be due to hemolytic anemia, liver disease such as hepatitis, or a blockage in your bile ducts or gallbladder. A high direct bilirubin in particular often points to a problem with the liver or with bile flow rather than with red blood cell breakdown.

Low bilirubin levels (hypobilirubinemia) are not usually a cause for concern but may be due to medicines such as antibiotics, birth control pills, sleeping pills, and seizure medicines.