What is bilirubin?

Bilirubin is made during the normal process of breaking down red blood cells. It is a yellowish substance found in bile, a fluid in your liver. This fluid helps digest food. A healthy liver moves most of the bilirubin from your body. If the liver is damaged, bilirubin can leak out into your blood.

If there is too much bilirubin in your blood, it can cause health problems. Bilirubin can also come out in the urine, causing it to look very dark.

Why is a bilirubin test done?

A bilirubin test is done to measure the levels of bilirubin in your blood.

If too much bilirubin is in your bloodstream it can cause jaundice, which can make your skin and eyes turn yellow. The results of the bilirubin test and signs of jaundice can help your doctor check your liver and determine if you have liver disease.

A bilirubin test is also used to determine jaundice in newborns. Many newborns do not have mature enough livers to get rid of bilirubin. High bilirubin levels in newborns can cause brain damage.

The test is usually done in conjunction with other tests for liver disease as part of a hepatic function panel. It can also be done to:

  • Diagnose hepatitis, cirrhosis, or other liver diseases
  • Find blockages in structures carrying bile from your liver
  • Monitor an existing liver disorder
  • Diagnose disorders related to red blood cell production problems
  • Test a patient who has history of drinking large amounts of alcohol
  • Test a patient who has a suspected drug toxicity

Test Details

How do I prepare for a bilirubin test?

No special preparations are necessary before the bilirubin test. Your doctor will let you know if there are any restrictions, such as what you can eat or drink before the test. This may be necessary if your blood is being tested for other conditions at the same time.

What should I expect during the bilirubin test?

During the bilirubin test, a blood sample is taken from your arm through a small needle. A little sting may be felt as the needle goes in.

After the test you will be able to go about normal activities. Later, you will discuss the results with your doctor.

Are there risks to the bilirubin test?

There are little to no risks to having the bilirubin test. There may be slight bruising or pain where the needle entered and exited your arm. This quickly goes away.

Results and Follow-Up

What might the bilirubin test results mean?

High levels of bilirubin could mean your liver is not functioning correctly. However, high levels can also be due to medications, exercise, or certain foods. Bilirubin is also a product of breakdown of red blood cells, and an elevated reading may be related to disorders of red blood cells and not liver disease.

Results which are not in the normal range do not necessarily mean there is a medical condition needing treatment. A benign liver disease called Gilbert’s syndrome may cause minor elevations of bilirubin and can be ignored.

Bilirubin is typically not found in urine. If it is, it can mean some form of liver damage or blockage is taking place.

In a newborn, elevated levels of bilirubin must be identified and treated quickly. These elevated levels can damage developing brain cells and result in learning and developmental disabilities, hearing and eye problems, and death.

Your doctor can provide more information as to what the results mean.

Last reviewed by a Cleveland Clinic medical professional on 06/14/2018.


  • U.S. National Library of Medicine. Bilirubin Blood Test. ( Accessed 9/13/2021.
  • American Liver Foundation. Liver Biopsy and Liver Function Tests. ( ( Accessed 9/13/2021.
  • Lab Tests Online. Bilirubin. ( Accessed 9/13/2021.

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