Which of the following has strong affinity for hemoglobin and acts in blood to act as "mop-up" molecule to bind hemoglobin?

Ans. c (Haptoglobin). (Ref. Robbin, Pathology, 7th ed., 624; Harrison, Internal medicine 15th ed., s608)Free Hb in plasma is promptly bounded by an alphal globulin, the haptoglobin that acts as 'mop-up' producing a complex that is rapidly cleared by mononuclear phagocyte system, thus preventing excretion in urine; hence in intravascular hemolysis serum haptoglobin is decreased.GENERAL FEATURES OF HEMOLYTIC DISORDERSGeneral examinationJaundice, pallorOther physical findingsSpleen may be enlarged; bossing of skull in severe congenital casesHemoglobinFrom normal to severely reducedMCV, MCHUsually increasedReticulocytesIncreasedBilirubinIncreased (mostly unconjugated)LDHIncreased (up to 10X normal with intravascular hemolysis)HaptoglobinReduced to absent