Probe, DAT on the sample of the red blood cell transfused, some times, blood donors appears with DAT positive. Try also, if you want, washing the red cells, before elution, with, cold LISS solution, in case you DAT is positivo for low avidity antibodies! Did u tested DAT in monospecific reactives (anti IgG and anti C3?), if you have a DAT positive with polispecific reagent, so you most look for the monospecificity