What is a Bilirubin Blood Test?

A bilirubin blood test measures the levels of bilirubin in your blood. Bilirubin is a yellowish substance made during your body’s normal process of breaking down old red blood cells. Bilirubin is found in bile, a fluid your liver makes that helps you digest food.

If your liver is healthy, it will remove most of the bilirubin from your body. If your liver is damaged, 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. Signs of jaundice, along with a bilirubin blood test, can help your health care provider find out if you have liver disease.

Other names: Total serum bilirubin, TSB

What is it used for?

A bilirubin blood test is used to check the health of your liver. The test is also commonly used to help diagnose newborn jaundice. Many healthy babies get jaundice because their livers aren’t developed enough to get rid of enough bilirubin. Newborn jaundice is usually not harmful and clears up within a few weeks. But in some cases, high bilirubin levels can lead to brain damage, so infants are often tested as a precaution.

Why do I need a bilirubin blood test?

Your provider may order a bilirubin blood test:

  • If you have symptoms such as jaundice, dark urine, or stomach pain. These could be symptoms of hepatitis, cirrhosis, or other liver diseases. They may also be signs of gallbladder disease.
  • To find out if there is a blockage in the bile ducts, the tubes that carry bile from your liver.
  • To check on an existing liver disease or disorder.
  • To diagnose disorders related to problems with breaking down red blood cells. High bilirubin levels in the bloodstream may be a sign of a condition called hemolytic anemia. In this condition, the body destroys red blood cells faster than it makes them.

What happens during a bilirubin blood test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

Your health care provider may tell you to fast (not eat or drink) for four hours before your blood test. If there are any other special instructions, your provider will let you know.

Are there any risks to the test?

There is very little risk to having a blood test. You may experience slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Normal results can vary, but high bilirubin levels may mean your liver isn’t working right. However, abnormal results don’t always mean you have a medical condition that needs treatment. Other things may cause higher than normal bilirubin levels, such as certain medicines and foods or strenuous exercise. To learn what your results mean, talk with your provider.