Do you have donor records or just patient records? If only patient records can your IS system choose not to convert records of patients it has flagged as deceased? Would this drop your numbers significantly? An institution i worked for went through a couple of such conversions and for one of them we did ,in fact,, check every patient record that had an antibody, but we had culled the deceased and we were a Blood Bank, not a donor center. It was still very tedious and we designated one tech to the project.