Orange-yellow pigment in bile, causing jaundice if it builds up in the blood and skin; the levels of bilirubin in the blood are used to diagnose liver disease. Serum total bilirubin is increased in hepatocellular damage (infectious hepatitis, alcoholic and other toxic hepatopathy, neoplasms), intra- and extrahepatic biliary tract obstruction, intravascular and extravascular hemolysis, physiologic neonatal jaundice, Crigler-Najjar syndrome, Gilbert's disease, Dubin-Johnson syndrome, and fructose intolerance. Disproportionate elevation of direct (conjugated) bilirubin is seen in cholestasis and late in the course of chronic liver disease. Indirect (unconjugated) bilirubin tends to predominate in hemolysis and Gilbert's disease. Decreased serum total bilirubin is probably not of clinical significance but has been observed in iron deficiency anemia. A yellow-orange compound produced by the breakdown of hemoglobin from red blood cells. Conjugated Bilirubin: Direct bilirubin bilirubin that has been taken up by the liver cells and conjugated to form the water-soluble bilirubin diglucuronide. Indirect Bilirubin: Unconjugated Bilirubin. Unconjugated Bilirubin: The lipid-soluble form of bilirubin that circulates in loose association with the plasma proteins; called also indirect bilirubin