Results: FC-CDC-XM was able to correctly identify all antibodies tested as specific to HLA class I (n ؍ 18) or II (n ؍ 4).Conclusions: The new FC-CDC-XM is more sensitive and more objective than the standard CDC-XM and can be used for pre-and posttransplant diagnoses and for the detection of other antibody-mediated cytotoxic reactions.