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
Direct coomb&;s test detects - 
Select and explain. 
A. Antigen in serum, B. Antibodies in RBC surface, C. Antigen in RBC surface, D. Antibodies in serum
B: Antibodies in RBC surface
Answer: B: Antibodies in RBC surface 
Explanation: Detection of antibodies or complements on red cell is detected by direct coombs test.Here patients red cell are mixed with sera containing Ab that are specific for human Ig or complement.If either of these is present on surface of ted cells,the antibodies cause agglutination which is easily appreciated visually as clumping. Reference : Robbins and Cotran Pathologic basis of disease.South Asia Edition volume 1.page no. 643