With an alpha thalassaemia frequency of 0·68; SAO frequency of 0·07, and G6PD deficient X chromosome frequency of 0.13, all entirely plausible for the Madang region of Papua New Guinea (Flint et al, 1986; Brabin & Brabin, 1990; Patel et al, 2004), the sensitivity of the OTOFT for beta thalassaemia drops to 0.74 in females and 0.69 in males (Fig4 marker A). Here, G6PD is linked to alpha thalassemia spectrum.