G6PD and malaria: However, according to these assays, female heterozygotes for the G6PD gene who have G6PD activity levels of 30 to 70% of normal may be identified as “G6PD normal” but remain at risk for hemolysis.8,10,11 The hemolytic risk with tafenoquine relative to that with primaquine has been characterized among healthy volunteers with normal G6PD enzyme activity and volunteers who were heterozygous for G6PD deficiency.8 However, a possible interaction between drug effects and malaria-induced hemolysis requires a formal evaluation of hemolytic risk among patients with P. vivax malaria.