Does anyone allow electronic crossmatch to be used in cases where a prior marrow transplant will never result in the usual reverse type on the patient (for example B to A)?  We have a discrepancy blood type test in our computer that doesn't require the usual truth tables be met that we currently use for these patients.  We require 2 separate specimens to be typed before we give any RBCs that aren't group O.  We require 2 individuals to review any results turned out using the discrepancy test (this doesn't mean mistakes couldn't happen).  We could have a patient with a cold agglutinin that would make an IS crossmatch incompatible (although maybe immunosuppressed patients won't make those?). I just want to see if anyone else has worked through all the logic involved in making sure patients are safely transfused yet the testing is appropriate to the need.

In the UK, the Guidelines would (quite correctly in my own opinion) NOT allow us to perform electronic issue on any sample, whatever the pathology, on a patient where the forward ABO type does not match the reverse ABO type (apart from Newborn babies).

The FDA Guidance on Computer Crossmatching calls out that patients with an ABO typing discrepancy should not be allowed to qualify for computer crossmatches. 

" If ABO typing discrepancies exist, you should not rely on a computer crossmatch. This is particularly important if there is mixed field red cell reactivity, 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 wrote our policy to include any non-straightforward ABO types for any reason will be required to get an IS or IAT crossmatch.