Useful For

The direct bilirubin is the terminology that represents the classic representation of conjugated bilirubin, that is, bilirubin bound to the glucuronide.  It is important to determine whether the liver cells are conjugating the bilirubin that is present in the serum in order to be able to differentiate causes for an increased bilirubin level.

Jaundice has been classified as unconjugated and conjugated hyperbilirubinemia.  Increased plasma-unconjugated bilirubin is commonly seen in hemolytic disorders, Gilbert’s syndrome, Crigler-Najjar syndrome, neonatal jaundice, and ineffective erythropoiesis and in the presence of drugs competing for glucuronide.  Increased plasma-conjugated bilirubin occurs with hepatobiliary disorders, including intrahepatic and extrahepatic biliary tree obstruction, liver cell damage, Dubin-Johnson syndrome and Rotor syndrome.