The United States Food and Drug Administration (FDA)21, the 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guideline22, and the updated 2015 National Institute for Health and Care Excellence (NICE) guideline23 suggested to limit the upper Hb target to 11~12 g/dL and avoid normalization of Hb level. Here, GSTM1 is linked to kidney disorder.