G6PD and G6PD deficiency: The only drug effective against relapse of P. vivax is primaquine, a seriously flawed drug that causes mild to severe and fatal acute hemolytic anemia in patients having an inborn deficiency of glucose-6-phosphate dehydrogenase (G6PD).17 This very complex disorder affects 400 million people globally, with an average prevalence in malaria endemic zones of 8%.18 Current technologies do not permit access to a diagnosis of G6PD deficiency where most patients live.