What are common causes of elevated serum levels of conjugated bilirubin?

Elevated serum levels of conjugated bilirubin typically indicate an issue with bilirubin processing or excretion. Conjugated bilirubin is the form of bilirubin that has been processed by the liver and is water-soluble, making it easier for the body to excrete via bile. Common causes of elevated conjugated bilirubin include conditions that obstruct bile flow and certain inherited disorders affecting bilirubin metabolism.

Biliary obstruction is a key factor that can lead to an increase in conjugated bilirubin levels. Conditions such as gallstones, tumors, or strictures can block the bile ducts, preventing bilirubin from being properly excreted into the intestine, leading to its accumulation in the serum.

Dubin-Johnson syndrome is another important condition associated with elevated conjugated bilirubin. This genetic disorder affects the liver's ability to excrete conjugated bilirubin into the bile due to a defect in the transport proteins, resulting in an increased level of conjugated bilirubin in the bloodstream.

In contrast, hemolysis primarily increases unconjugated bilirubin due to the breakdown of red blood cells, leading to a high production of bilirubin that the liver is not able to process quickly enough. Gilbert's syndrome is characterized by unconjugated hyperbilir