**7.3. Cytochemical staining assay**

The Cytochemical staining assay is based on the intracellular reduction of the tetranitro blue tetrazolium (TNBT) by the G6PD via exogenous electron carrier 1-methoxyphenazine methosulfate and TNBT is reduced to dark-colored water-insoluble formazan, which can be determined by light microscopy (Peters & Van Noorden, 2009).
