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I was wondering if Amy is a blood banker.

missing serum reactivity, or apparent change in blood type following hematopoietic stem cell transplantation.Under those circumstances, your procedures should provide for compatibility testing using serologic crossmatch techniques." I haven't worked on the bench for a long time. Have I missed something? I fail to see how a serologic crossmatch technique will provide any meaningful information about compatibility if there is "missing serum reactivity".

ALG is anti-lymphocte globulin and ALT anti-thymocyte globulin. These are heterophile antibodies that are given to patients as treatment (or, rather, part of treatment) and, when first given, often cause a positive DAT, which disappears relatively quickly in vivo, so that blood taken immediately after dosing has a positive DAT, but blood taken a little later has a negative DAT. There may well now be other such drugs, as I came across this effect a few years ago now.

Thank you all for your input. With regard to the comment that the post was long....I tend to like to explain things thoroughly so readers have all of the information I have, and know what my thoughts are up to that point. Sorry, just my style. ABsub did also occur to me, but in all honesty, I have only rarely seen this in my 30+ years (just lots of AsubB). Also not sure if it was just weak due to age so would not want to "label" them as ABsub if 6 months from now, they typed 4+ with Anti-B. So was a little nervous about coming to that "official" conclusion. So we did make the recommendation that if they really wanted to know, they could try submitting a new specimen in about 6 months. I agree that there could be a different Low Incidence Antibody that caused the transfusion reaction (we only tested what we could get from our panels). We are sending pre and post specimen plus leftover platelets to the Red Cross to see what they come up with. They may or may not elect to run a panel of some Low Incidence Antigens from their frozen inventory; but of course they can't test every Low Incidence Antigen so it would just be a "hit or miss." But I guess what is still just odd to me is that the DAT was negative before the transfusion (just that morning; was just sent because the patient was being seen by their Oncologist and has been using blood products steadily, so they wanted us to have a specimen available should they need to transfuse more RBCs in next few days); then clearly positive right after the transfusion; and there was definitely an Anti-Lua coating the cells (but also a mystery as to why the strength of the DAT would so obviously weaken in just a few hours, if no evidence of hemolysis). Also, with regard to the comment from BankerGirl about why we were calling it a hemolytic transfusion reaction. We had called the Red Cross Medical Director right after we discovered the Positive DAT and he instructed us to do that; however, our Medical Director did not state that on the Transfusion Reaction Report; but in fact, stated that the reaction may not have even been related to the transfusion; could have been coincidental timing (but that still doesn't explain a Negative DAT becoming Positive from Pre to Post). So is the suggestion then that while we eluted the Lua.....that had we performed an eluate on the negative DAT cells from the morning, we may also have eluted it then but it is just that it is not present on enough cells to have resulted in the Positive DAT (i.e. as an explanation as to why the DAT changed but no Anti-Lua was identified in the platelet plasma)? I am still trying to make sense of that part; that if it was not the cause of the reaction and was not in the platelets, the assumption would have to be that it was already present and coating the cells prior to the transfusion; just not enough to cause a positive DAT; but enough to come off in a concentrated eluate? The patient had received numerous red cell transfusions over a long period of time; so there certainly could have been a small population of transfused cells that were Lua POS to which the patient's Anti-Lua attached? Also, Antibody Screen Negative, so no "free" Anti-Lua (unless low titer). If Red Cross comes up with anything more concrete, I will pass that along; but I really appreciate your input on this mystery! Brenda Hutson

Never mind. I just read it again.