In patients of obstructive jaundice the value of serum bilirubin plateaus around 25-30 mg% since the water soluble bilirubin is excreted the urine. However in concomitant renal failure, loss of conjugated bilirubin the kidney fails and leads to extremely high values. Another reason can be a simultaneous overproduction of unconjugated bilirubin due to haemolysis, sepsis and sickle cell anaemia.