I also have a problem with people going straight to a prewarm procedure. The problem is that they are not THINKING first. They get reactions that scream warm auto and they prewarm. They get a weak reacting panel and instead of considering doseage, they prewarm. When the prewarm doesn't make all their problems go away, they stop dead, instead of addressing what they actually have. I am working on them to try a cold antibody screen first. IF that is positive, then prewarm. If it's not positive, then they need to try a different enhancement method (step down from solid phase), another panel, think doseage, all the good stuff we do to solve a problem. In other words, use a plan of action instead of the hit-and-miss method. I did have a tech prewarm away a developing anti-Fy(a) one evening. The reactivity was weak, but the pattern was there with doseage. The patient was discharged immediately after transfusion and sent home 100+ miles away, so all we could do was notify her surgeon (who probably didn't do anything about it). The next time we saw the patient was for a surgical referral months later. Her anti-Fy(a) was then reacting 3-4+. Did she have any kind of reaction? If she did, we never heard about it.