This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Screening tests for cell defects : 
Select and explain. 
A. Isohemagglutinin titers, B. CD4 levels, C. Nitroblue tetrazolium dye test, D. Candida albicans intraden-nal skin test
A: Isohemagglutinin titers
Answer: A: Isohemagglutinin titers 
Explanation: None