We occasionally have these on the Echo. At first I sent these to our ARC reference lab assuming they were warm autos. On their advice, I now perform a DAT, tube screen with LISS and a major crossmatch. If these are all negative, I call it a negative screen and move on. No one has had any sort of reaction. I have also had the rare cold, Sda, and Lewis react on the Echo like this. Some patients who have fresh chemo treatments and then come in for transfusions have had these reactions too.