Direct Coomb's test is positive in hemolytic anemia due to:: (A) Paraxysmal cold hemoglobinuria, (B) Paroxysmal nocturnal hemoglobinuria, (C) Idiopathic thrombocytopenic purpura, (D) Hemolytic uremic syndrome
Answer is A. Paroxysmal cold hemoglobinuria: Caused by the presence of cold-reacting autoantibodies (anti-P Ab) in the blood - Hence, Direct coombs test is positive. Characterized by the sudden presence of hemoglobinuria, typically after exposure to cold temperatures.