In many Chinese hospitals, blood units are fully crossmatched due to following reasons:one is that hospital blood banks do not have the manpower and resources to perform complete antibody investigation, another is that the blood center do not perform the antibody screening for donor unit, and the hospital do not test it either since who can not chage the testing fee from donor.In this situation, we have to perform both major and minor XM. There is no problem to do so with conventional tube ITA, but the problems present when new technology introduced.The microcolumn technology is more sensitive than tube one,the recipient'DAT positive will result in minor XM's positive. however, the DAT is not the routine tesing for recipient.