This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Low serum haptoglobin in hemolysis is masked by ? 
Select and explain. 
A. Pregnancy, B. Liver disease, C. Bile duct obstruction, D. Malnutrition
C: Bile duct obstruction
Answer: C: Bile duct obstruction 
Explanation: Ans. is 'c' i.e., Bile duct obstruction Haptoglobin o Haptoglobin is a transpo glycoprotein which binds free hemoglobin in plasma and carries it to the reticuloendothelial system. It is synthesized in the liver. o A decrease in haptoglobin levels (with normal liver function) occurs when there is excess of hemoglobin in the plasma due to intravascular hemolysis ---> free hemoglobin in plasma bound to haptoglobin and this complex is rapidly cleared by mononuclear phagocytic system. o In biliary obstruction the serum haptoglobin level is increased and this may mask the decrease in serum haptoglobin due to hemolysis.