GSTM1 and anemia (phenotype): The World Health Organization has acknowledged that blood transfusions are lifesaving interventions with an essential role in patient management.[1] Thus, providing hemoglobin (Hb) as oxygen carrier to prevent manifest anemia‐related tissue hypoxia, transfusion of packed red blood cells (pRBCs) is implemented in therapy regimes of acute or chronic anemia.[2, 3] However, chronic Hb delivery comes with substantial side effects.