This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
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: Ans. (a) Phagocytes(Ref Robbins 9th/pg 238; 8th/pg 55)DiagnosisNitroblue-tetrazolium (NBT) test: Most widely known test for chronic granulomatous disease.#Depends upon direct reduction of NBT in phagocytes by superoxide free radical to form an insoluble formazan Q#This test tells whether or not PHOX enzymes are present, not how much they are affected Q