 This includes ABO/Rh typing of the unit and of the recipient, and an antibody screen of the recipient.Electronic cross-matching can only be used if a patient has a negative antibody screen, which means that they do not have any active red blood cell atypical antibodies, or they are below the detectable level of current testing methods.If all of the data entered is compatible, the computer will print a compatibility label stating that the unit is safe to transfuse.