Question

Our liver conjugates 250-300 mg bilirubin per day under normal circumstances but it is capable of conjugating much more. What is the upper end per day after which it won’t be able to conjugate leading to increased unconjugated bilirubin in serum?

Answer 1

The liver normally conjugates 250-300 mg of bilirubin daily, but this is not the upper limit of its capacity. In diseases affecting liver function, bilirubin levels can reach a point where the liver cannot conjugate further, typically around or above 20 mg/dl, leading to increased serum levels of unconjugated bilirubin.

Step-by-step explanation:

Under normal circumstances, the liver conjugates 250-300 mg of bilirubin per day. However, in conditions where the liver's functioning is compromised, such as in hepatic or parenchymatous jaundice, Crigler-Najjar syndrome, or Gilbert's disease, the capacity to conjugate bilirubin is significantly reduced. The liver has a remarkable ability to conjugate more than the baseline amounts of bilirubin under increased demand; however, this capacity is not limitless.

In cases like unconjugated hyperbilirubinemia, if serum bilirubin levels exceed 20 mg/dl, it indicates the liver's capacity to conjugate bilirubin is overwhelmed. With increased levels, the unconjugated bilirubin in the serum rises, as the liver enzyme UDP glucuronyl transferase, responsible for bilirubin conjugation, reaches its maximum activity and cannot process more bilirubin effectively.