“…This is in contrast to studies which do not assess the role of multiple transfusions to an individual patient, some of which might be ABO identical and some not, and therefore could not assess the overall clinical outcomes following ABO identical transfusions. 2 More problematic are studies that claim to find no benefit of ABO identical platelet transfusions, which include patients in the ABO identical group based solely upon a patient's first transfusion, and then ignoring subsequent, perhaps numerous ABO nonidentical transfusions. 3,4 This is concerning as it makes no scientific sense to include in the ABO identical group a patient who received a first ABO identical platelet transfusion and then received one or more ABO nonidentical transfusions.…”