GSTM1 and anemia: Of the remaining five RBC transfusions without a documented trigger, one had a Hb > 90 g/L and this patient was not recorded as having a cardiovascular admission diagnosis or condition, and was only reported to have minor bleeding, and this was, therefore, likely to be inconsistent with the PBM guidelines; one was for major bleeding and, therefore, consistent with the guidelines; the remaining three had Hb levels ≤ 90 g/L and were assumed to be consistent with the PBM guidelines based on clinically significant anaemia and/or ACS.