Follow-up tests include:
- Serologic crossmatch by IAT of any transfused O negative RBC to identify if a transfusion reaction is likely;
- Antibody investigation to identify the patient's antibody, including
- direct antiglobulin test (DAT)
- Antigen phenotyping of patient and all donor RBC for the antigen corresponding to any identified antibody;
- Serologic crossmatch by IAT of any donors found to be antigen-negative.