- WHO class III G6PD-deficiency or G6PD-normal status must be documented by enzyme activity and cytochemical staining. G6PD genotype must confirm WHO class III G6PD deficiency or G6PD-normal status prior to TQ dosing in all parts of the study (i.e., P. vivax infected subjects may commence CQ therapy whilst the cytochemical staining, enzyme activity and G6PD genotype are being determined).