This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
All of the following are associated with coombs positive hemolytic anemia except - 
Select and explain. 
A. Thrombotic thrombocytopenia purpura (TTP), B. Scleroderma, C. SLE, D. PAN
A: Thrombotic thrombocytopenia purpura (TTP)
Answer: A: Thrombotic thrombocytopenia purpura (TTP) 
Explanation: Coombs is positive only in immune hemolytic anemias where there is hemolysis of RBCs by antibodies produced in the body which is the case in SLE ,PAN & Scleroderma. While in TTP hemolysis occurs due to trauma to RBCs due to Microangiopathic hemolysis, seen in TTP &HUS Ref Robbins 9/e pg 448-449