Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Australian and New Zealand Intensive Care Research Centre (ANZIC-RC), Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Electronic address: zoe.mcquilten@monash.edu. Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Systematic Reviews Initiative, NHS Blood and Transplant/Oxford University Hospitals NHS Trust, Oxford, United Kingdom. Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Systematic Reviews Initiative, NHS Blood and Transplant/Oxford University Hospitals NHS Trust, Oxford, United Kingdom. Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.