Most antibody identification studies are performed in a transfusion service setting. Serological problem solving protocols used for this testing must strike a balance between providing identification of clinically significant alloantibodies and resolution of the problem with minimal delay in patient care. The variety of extremely sensitive manual and automated antibody detection/identification methods available for use presents unique challenges for a transfusion service. What clues can be obtained from the patient's history when evaluating a positive antibody screen? How do you decide when weak reactivity in a sample is important? What information can be used to support a decision to switch to an alternate test method? What test methods should be available for antibody resolution studies in a transfusion service? How can an antibody identification protocol be presented in a manner useful to the front-line technologist? These issues will be addressed in a lecture and case study format with plenty of opportunity for attendees to discuss issues from their own institutions.