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Bilirubin Blood Test

Bilirubin Blood Test

What Is a Bilirubin Blood Test and Why Is It Done?

A bilirubin (bil-ih-ROO-ben) blood test measures how much of a pigment, or color, called bilirubin is in the blood.

Doctors might order this test for:

  • newborn babies, especially those born early
  • babies or kids who have jaundice (JON-diss), a condition where the skin and whites of the eyes look yellow
  • kids with a medical condition that makes high bilirubin levels more likely, such as a liver problem

What Is Bilirubin?

The yellowish pigment bilirubin comes from the breakdown of red blood cells. The liver changes bilirubin so the body can excrete (get rid of) it.

Top Things to Know

  • The bilirubin blood test checks the level of a pigment (color) in the blood called bilirubin.
  • Doctors may do the test for newborns, babies or kids with jaundice, or children who might have a liver problem.
  • Kids might need to stop taking certain medicines or not eat or drink before the blood test.
  • Your doctor can explain what it means if bilirubin levels are high or low.

How Can I Help My Child Prepare for a Blood Test?

To help kids get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is nervous about it, work together on ways to stay calm. Deep breathing or even imagining being in a place that makes your child feel safe and relaxed can help.

What Do Bilirubin Test Results Mean?

Your doctor will explain what the results of the test mean for your child. “Normal” bilirubin levels can vary based on things like age and gender.

High Bilirubin Levels

Newborn babies born early often have high bilirubin levels from lots of red blood cells breaking down. This leads to jaundice.

Sometimes high bilirubin levels mean there's a liver problem like hepatitis or Gilbert’s syndrome (when an enzyme has trouble breaking down bilirubin). High levels could also happen when too many red blood cells are breaking down due to things like a blood disorder or a reaction to a blood transfusion.

Problems with the gallbladder (an organ in the digestive system) or tubes in and near the liver called bile ducts can also raise bilirubin levels.

Low Bilirubin Levels

A low bilirubin level usually isn’t anything to worry about. Some medicines — like antibiotics, seizure medicines, and birth control pills — can lower the level.

What Else Should I Know?

If you have questions about the bilirubin test, or what the results mean, speak with your doctor.

Medically reviewed by: Larissa Hirsch, MD
Date reviewed: January 2026