A 3-year-old male child is brought by his father with complaint of recurrent infections despite proper treatment and hygiene. While reviewing his history, pediatrician notices that the child has been infected multiple times with S. aureus, Pseudomonas & E. coli. Which of the following test will be useful to diagnose condition of the child?

Given scenario suggests diagnosis of Chronic granulomatous disease. Chronic granulomatous disease. Due to NADPH oxidase defect Subtypes: X linked recessive Autosomal recessive Gp 91 PHOX defect Gp 47 PHOX defect Gp 67 PHOX defect C/F: Recurrent infections: by catalase positive organism.Eg- S. aureus, Pseudomonas, Nocardia Granuloma formation Diagnosis: Nitroblue-tetrazolium test- No O2 radicals - No formazan - No colour Flow cytometry: Done using Dihydro Rhodamine (DHR)