G6PD and G6PD deficiency: The WHO definitions for severity of G6PD deficiency primarily categorize hemizygous G6PD-deficient males, as well as women homozygous for G6PD-deficient alleles, as G6PD deficient (less than 30% of normal); most heterozygous women are included in the intermediate G6PD activity range of 30–80% normal; above 80% is considered to be normal G6PD activity.