A recent retrospective study showed that one-third of anemic (Hb <12 g/dl) patients received at least one RBCT at the discretion of the attending physician; although anemia was associated with a longer length of ICU stay and duration of mechanical ventilation requirements, no significant benefit from RBCT was found and no specific transfusion strategies were recommended in this patient population [82]. Here, GSTM1 is linked to anemia.