rwalter

Another thought occurred to me, Malcolm: Perhaps they treated the baby's cells with dithiothreitol (DTT) to remove the maternal anti-D which presumably would have given them a positive DAT. The DTT treatment could have denatured the k antigen, causing a false negative typing. I'll stop now and wait for you to give us the correct answer. Thanks for making me think this morning. -Rohn

Did you test the baby's sample with a monoclonal anti-k reagent? Perhaps the baby lacks a common epitope of the k antigen, producing a false negative (admittedly grasping at straws).

In this case, many facilities go from doing IS crossmatch to simply issuing ABO compatible RBC units, with no crossmatch at all. The premise is that testing against the original sample has no real value, as whatever is circulating in the patient now has little resemblance to the original.

It's my understanding that once you go into the massive transfusion scenario, the standard allows you to do "abbreviated" compatibility testing. In our facility, once we are past the first ten RBC units, we go to handing out type compatible blood that is not serologically crossmatched. The IS crossmatch on the original sample is pretty much meaningless at that point. We get a new sample after three days.

It occurs to me that you might want to send a sample of the patient serum, if still available, to the manufacturer of the panels you were using to evaluate the unexplained reactivity on the cell labeled "f negative." f antigen status is often based on the presumptive Rh genotype based on the phenotype. Perhaps that cell is actually f positive. Adsorption-elution studies could probably resolve the question of the unexplained reactivity. For sure, that's beyond the scope of the average transfusion service, but it may interest the panel manufacturer.

Is anyone using the Accsense system for monitoring BB refrigerators/freezers/platelet incubators? Our hospital system had already bought it before I started here, and it's not validated and not officially in use. I would like to make it our primary method of temperature monitoring, since it's easy to check any device from any internet computer. My concern is the style of probes used; they apparently are not designed for immersion in liquid. The are "air probes." Any input would be helpful.