A recent study of the factors associated with IDA in Ugandan children (6–23 months of age) examined the enhancement of Hb to differentiate IDA from total anaemia by the addition of the red blood cell distribution width (RDW) in the presence of microcytosis or the addition of the Mentzer index (mean cell volume/red blood cell count) [35]. This evidence concerns the gene GSTM1 and anemia (phenotype).