The Transfusion and Treatment of Severe Anaemia in African Children Trial (TRACT) was designed as a multicentre trial to establish transfusion and treatment strategies in sub-Saharan Africa and investigated: (i) whether an immediate transfusion in children with uncomplicated severe anaemia (Hb 40–60 g/l) would improve outcomes and (ii) whether 30 versus 20 ml/kg whole blood might improve outcomes, defined as mortality to day 28 (primary outcome) and day 180, and the need for additional transfusions and relapse of severe anaemia.12 This evidence concerns the gene GSTM1 and anemia (phenotype).