This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (R.B.C), Subject name: Pathology
Direct coomb's test positive is seen in all except? 
Select and explain. 
A. ABO incompatibility, B. Hemolytic d/s of newborn, C. Aplastic anemia, D. Autoimmune hemolysis
C: Aplastic anemia
Answer: C: Aplastic anemia 
Explanation: Ans. (c) Aplastic anemia(Ref: Wintrobe 13th ed/Page 576)Coomb's test is positive in Immune hemolytic anemiaThey can be of 2 types:#Direct Coomb's test- Detects Antibody on RBC SurfaceQ#Indirect Coomb's test- Detects Antibody in SerumOut of the given options: Aplastic anemia is not a hemolytic anemia and so is automatically the answer here.