GSTM1 and G6PD deficiency: Although the current analysis was not designed to prove this hypothesis, the data show that using a combination of spectrophotometry and flow-cytometry is a feasible approach for the study of the phenotypic interaction of G6PD deficiency and haemoglobinopathies and could be used in clinical trials performed in populations where Hb variants are very common, for example in Cambodia and Laos.