The antiglobulin phase crossmatch is the same indirect antiglobulin test IAT used for antibody screening, only instead of reagent RBCs we use the donor’s RBCs. One question I like to ask my students is to describe the difference between the IAT and the antibody screen. Most don’t realize they are the same thing, the same procedure, i.e. mixing plasma/serum with RBCs and then detecting a reaction using the AHG reagen
In Medinfo, the AHG phase crossmatch will be required unless the criteria for electronic crossmatch have been met (see my previous post on this topic). In emergency mode, one can also do a class II release using immediate-spin to detect ABO incompatibility. Medinfo will check the historical records for previous antibodies.
Notice that the process includes contingencies for room and even lower temperature conditions as well as immediate-spin.
I warn my students that we can make any tube, gel or glass-bead well react if we do not strictly adhere to the manufacturer’s recommendations. The simplest example is to leave the reaction mixture to incubate longer than the time limit for LISS (e.g. 60 minutes).
If the antiglobulin phase crossmatch is positive (i.e. nonnegative reactions), then the unit is rejected or a least-incompatible crossmatch mode is activated. The latter requires the transfusion medicine physician to specifically approve the allocation and release of this component.
The following is the Medinfo process I used:
To Be Continued