GSTM1 and anemia (phenotype): Measurements of Ret He provide useful information in diagnosing anemia, iron-restricted erythropoiesis, and functional iron deficiency and response to iron therapy during rHuEpo therapy [46–49]; Ret He, generated by all Sysmex XE analyzers (Sysmex Corporation, Kobe, Japan), has been recognised as a direct assessment of the incorporation of iron into erythrocyte Hb and a direct estimate of the recent functional availability of iron, thus provides the same information as CHr [50–52].