“…Although the literature contains many cases of antibody-mediated delayed hemolytic transfusion reaction (DHTR) in which subsequent retesting of pretransfusion specimens showed no antibody by "usual" or "standard" techniques, no information about what serum: cell ratio was employed is provided.4, 8-11, [14][15][16][17]20,21,[24][25][26][27]32 In order to minimize errors in in vitro tests for detection of clinically significant antigens and antibodies, it is important to I) standardize pretransfusion test methodology by adopting an optimum serum:cell ratio, 2) test the drop delivery volume of dropper pipettes used in antibody detection! compatibility tests as part of the quality control of equipment, 3) promote standardization of the concentration of commercial reagent red blood cells and the drop delivery volume of their vial droppers, and 4) save pretransfusion samples for 14 days after the patient's transfusion.…”