A total of 435 (57%) of 764 of the respondents reported that they used a different Hb threshold for RBC transfusion in patients with acute brain injury following TBI (n = 349), SAH (n = 279), ischemic stroke (n = 181), and HIE (n = 109), whereas only a few considered that a different transfusion policy was needed for patients with ICH (n = 88), postneurosurgery (n = 88), seizure/SE (n = 33), CNS infections (n = 27), or encephalitis (n = 18). The gene discussed is GSTM1; the disease is encephalitis.