Topic overview

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The lesson traces bilirubin from heme breakdown to excretion. It introduces the conversion of heme to biliverdin and unconjugated bilirubin, albumin-bound transport to the liver, hepatocyte uptake, and UGT1A1-mediated conjugation. It then follows conjugated bilirubin into bile and describes its conversion by intestinal bacteria to urobilinogen, including its main routes of excretion and recycling. Laboratory assessment includes the direct and indirect Van den Bergh reactions. The topic also compares prehepatic, hepatic, and post-hepatic jaundice, surveys hereditary hyperbilirubinemias, and introduces neonatal jaundice and drug effects on bilirubin metabolism.