When we have a suspected transfusion reaction a process of investigation is initiated: clerical checks, DAT on pre/post-tx specimens, urine for blood, ABORh on post specimen., visual exam of pre/post specs for hemolysis/icterus. If all of these are negative, the pathologist will provide an interpretation based on the reaction defined by the Nursing staff. If the investigation indicates a possible hemolytic transfusion reaction an entirely different process is initiated . . . HOWEVER, just because a reaction does not appear hemolytic it cannot be assumed that a reaction has not occurred as there are many types of reactions to blood products the majority of which are not hemolytic.
It would behoove you (and your Medical Director) to research the literature to discover these and then develop the processes of investigation according to the BB standards in your area of the world.