I'm wondering if the most common current practice is to crossmatch red blood cell units with the adsorbed plasma or do most facilities just issue antigen negative units without crossmatching them first with adsorbed plasma. (Either way, documented as least incompatible.)

We do not do our own adsorptions so we generally get our units from ARC reference in the case of a warm auto. They will send us AHG compatible with adsorbed plasma and antigen negative if there is a clinically significant antibody underlying the warm auto. At our facility, we do an AHG crossmatch and give least incompatible and again, antigen negative for an underlying antibody.

I worked for a hospital that did their own reference work and often for warm autoantibodies we would do a 30 minute incubation with no LISS AHG technique. Often times the warm auto would not react because they are sometimes LISS sensitive. I have had favorable results using this technique.

If you try hard enough, you can usually autoabsorb an auto ab (unless the pateint has been recently transfused), then you can issue crossmatch compatible, antigen negative red cells. I have a problem with "least incompatible" - it's like being "a little pregnant". Usually, with an warm auto situation, I tell the docs that the patient will handle the transfused cells as well as they handle their own, ie, they will be coated with antibody and removed.

We try to send segments to our referrence lab for crossmatching with the adsorbed sera and of course use antigen negative units if alloantibodies are also present.

When you say "issue ag. neg. with out crossmatch" I assume you mean that the patient's extended phenotype is known? We crossmatch with adsorbed serum but many of our hospitals can not do the adsorptions themselves. I, like David, do not issue "least incompatible" units. I tell the hospital that the units will be incompatible when they crossmatch with unadsorbed serum and just that. We use phenotypically similar units whenever we can not adsorb the auto away completely. Obviously we can not tell them that we have covered ALL antigens, but we do all of the "common" ones.