In the absence of optimal Hb thresholds to initiate RBCT in this setting, an international survey was conducted to investigate at which Hb level clinicians would initiate RBCT in patients with acute brain injury [17]; among 868 responses, 54% reported an Hb threshold of 7–8 g/dL to initiate RBCT in this setting, although half of these respondents would use a different threshold (i.e., closer to 9 g/dL) in case of systemic and cerebral triggers. The gene discussed is GSTM1; the disease is brain injury.