This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood disorder, Subject name: Pathology
A newborn with ABO incompatibility, the characteristic feature on peripheral smear is the presence of: 
Select and explain. 
A. Microspherocytes, B. Fragmented RBC, C. Polychromasia, D. Elliptocytosis
A: Microspherocytes
Answer: A: Microspherocytes 
Explanation: In ABO hemolytic disease of newborn -Peripheral blood smear shows numerous spherocytes (predominate) , occasional nucleated red cells, anisocytosis and polychromasia. -The blood film in ABO hemolytic disease of the newborn (ABO HDN) is marked by the presence of microspherocytes. -The spherocytosis is attributed to loss of membrane surface area when the spleen removes antigen-antibody complexes from the affected cell.