Description of the blood bank’s workflow in establishing the recipient’s ABO type and detection of unexpected erythrocyte antibodies other than anti-A and/or anti-B. The times listed represent the ideal turnaround times. The amount of time required to investigate a positive antibody screen and find antigen negative units depends on the nature and number of the antibody(ies) detected. *The electronic crossmatch can be performed if the patient’s current antibody screen is negative along with any historical antibody screens.