DefinitionBilirubin is a yellowish pigment found in bile, a fluid produced by the liver.This article discusses the laboratory test done to measure bilirubin in the blood. Total and direct bilirubin are usually measured to screen for or to monitor liver or gallbladder problems. Large amounts of bilirubin in the body can lead to jaundice.A test may also be done to measure bilirubin in a urine sample. For information on that test, see: Bilirubin - urine.Alternative NamesTotal bilirubin - blood; Unconjugated bilirubin - blood; Indirect bilirubin - blood; Conjugated bilirubin - blood; Direct bilirubin - bloodHow the test is performedA blood sample is needed. For information on how this is done, see: Venipuncture.The laboratory specialist spins the blood in a machine called a centrifuge, which s