Recently, while training a new employee on crossmatches performed on the Echo, I purposely pulled a AB+ unit and attempted to crossmatch it to a A+ patient. The unit should have been incompatible, right?? Not so. So I sent a tech service request to immucor, and the response that I received back was that this is just one of those unfortunate events because the crossmatch is only IgG it would not pick up incompatibilities. I then ran a totally different A+ patient, and lo and behold the unit was 3+ incompatible. I tested the unit against the original unit, and compatible again. Whats up with this? We do perform an immediate spin crossmatch on all crossmatches done on the instrument, and we should detect any incompatibilities at that time, but it just grates on my weak and feeble mind that the instrument will not detect this obvious incompatibility. Surely someone can give me an answer that I can live with, as it is, I may not utilize the crossmatch capabilities of the instrument.