The study by Turgeon et al. involved adults (≥ 18 years) experiencing moderate to severe TBI, characterized by a Glasgow Coma Scale (GCS) score of 3–12 and anemia (Hb ≤ 10 g/dL), while excluding individuals who received transfusions after ICU admission but prior to randomization. This evidence concerns the gene GSTM1 and anemia (phenotype).