This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Nitroblue tetrazolium test is used for 
Select and explain. 
A. Phagocytes, B. Complement, C. T cell, D. B cell
A: Phagocytes
Answer: A: Phagocytes 
Explanation: Ref, Harrison pg 76 In immunohistochemistry the alkaline phosphatase is often used as a marker, conjugated to an antibody. The colored product can either be of the NBT/BCIP reaction reveals where the antibody is bound, or can be used in immunofluorescence. The NBT/BCIP reaction is also used for colorimetric/spectrophotometric activity assays of oxidoreductases. One application is in activity stainsin gel electrophoresis, such as with the mitochondrial electron transpo chain complexes. Nitro blue tetrazolium is used in a diagnostic test,paicularly for chronic granulomatous disease and other diseases of phagocyte function. When there is an NADPH oxidase defect, the phagocyte is unable to make reactive oxygen species or radicals required for bacterial killing. As a result, bacteria may thrive within the phagocyte. The higher the blue score, the better the cell is at producing reactive oxygen species.