This test looks for bilirubin in your blood or urine.

Bilirubin is a substance made when your body breaks down old red blood cells. This is a normal process. Bilirubin is also part of bile, which your liver makes to help digest the food you eat.

A small amount of bilirubin in your blood is normal. Healthy adults make 250 to 350 milligrams (mg) of bilirubin each day.

Some bilirubin is bound to a certain protein (albumin) in the blood. This type of bilirubin is called unconjugated, or indirect, bilirubin. In the liver, bilirubin is changed into a form that your body can get rid of. This is called conjugated bilirubin or direct bilirubin. This bilirubin travels from the liver into the small intestine. A very small amount passes into your kidneys and is excreted in your urine. This bilirubin also gives urine its distinctive yellow color.

This test is often done to look for liver problems such as hepatitis, or blockages such as gallstones.