Definition of Bilirubin - blood:

Bilirubin is a yellowish pigment found in bile, a fluid made by the liver.

This article discusses the laboratory test that is done to measure bilirubin in the blood.

A small amount of older red blood cells are replaced by new blood cells every day. Bilirubin is left after these older blood cells are removed. The liver helps break down bilirubin so that it can be removed by the body in the stool.

See also: Bilirubin - urine

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture

How to prepare for the test:

You should not eat or drink for at least 4 hours before the test. Your health care provider may instruct you to stop taking drugs that affect the test.

Many drugs may change the bilirubin levels in your blood. Make sure your doctor knows which medications you are taking.

Why the test is performed:

Large amounts of bilirubin in the blood can lead to jaundice. Jaundice is a yellow color in the skin, mucus membranes, or eyes.

Jaundice is the most common reason to check bilirubin levels.

• Most newborns have some jaundice. The doctor or nurse will often check the newborn's bilirubin level. See: Newborn jaundice
• The test may also be done in older infants, children, and adults who develop jaundice.

A bilirubin test will also be done if your doctor thinks you may have liver or gallbladder problems.