We started using the computer crossmatch in the old Hemocare system in 1997. Back then you had to apply for a variance from FDA. FDA made me jump through hoops before they would grant the variance. They did not publish the guidance until 6 months after we applied. Had to prove the system would not you set up and issue an incompatible product, i.e., issue an A to an O or AB, etc.; that you could not perform an EC on someone with an antibody; that there were two ABO/Rhs on file. We had to send them the evidence that we crossmatched every ABO group against every ABO group to prove the above. The next year I guess they decided that we were not killing people and so you did not have to apply for a variance anymore, but, had to have your validation available. Have to redo the validation with every software upgrade.