Useful For

This orderable is used to determine individually the conjugated (direct) bilirubin, unconjugated (indirect) bilirubin, and the calculated total bilirubin. 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 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.

Neonatal bilirubin, the sum of the measured Direct (Conjugated) Bilirubin and Indirect (Unconjugated) Bilirubin, which is increased in erythroblastosis fetalis (hemolytic disease of the newborn), which causes jaundice in the first two days of life.  Other causes of neonatal jaundice include physiologic jaundice, hematoma/hemorrhage, hypothyroidism, and obstructive jaundice.