SundaySD

The best solution is to get a smart fridge.  I worked at a busy hospital where they had one we used to store blood in it, daily. It looked a lot like the following picture. We used to put blue tags on O Positive and Pink tags on O negatives. The nurses did not have to think too much, just to grab the units with blue tags for boys and pink tags for girls.

Most of our antibodies to gel diluent react only with the pre-diluted reagent cells, but not in cells suspended in MTS diluent 2 (auto control, XMs).  There are no antibiotics in the diluent 2 because those suspensions are discarded promptly whereas the reagent cells must remain stable for weeks.   If there are antibiotics in the gel itself, we have not seen reactions to that, but it makes sense.

When the major hematology and transfusion medicine textbooks acknowledge the data showing that ABO mismatched transfusions don't provide hemostasis, actually increase bleeding, and increase platelet transfusion refractoriness, then hematologists will change their approach.  Probably some time before the heat death of the universe. Instead, one major textbook quotes methodologically unsound data from a study that classified platelet transfusions as ABO identical based upon the first transfusion, even if large numbers of  ABO mismatched transfusions were subsequently given to that patient. Total scientific nonsense.  
No doubt medical education is also to blame. I've been here 42+ years and haven't been invited to give a single talk to medical students about transfusions for many years (this is changing in 2023).  The curriculum bears little resemblance to what physicians need to know, unfortunately.  Highly dysfunctional when the single most frequently performed inpatient procedure, transfusion, doesn't have a major role in the curriculum. Ah well.

"Since AB+ people are considered the "universal recipient" , we give them any type platelets, usually starting with the one with the closest out date. "
I grant you that this is widely shared idea in our field for decades. It is also seriously wrong.  It prioritizes inventory management over patient wellbeing.  Our approach to ABO and platelets is distinctly different from ABO and red cells with no rational basis.  Antibody and complement destroy red cells and platelets equally well.  The only difference is that instead of free hemoglobin being released, it's mediators such as VEGF, IL-6 and other platelet pro-inflammatory, immunomodulatory and pro-thrombotic granule contents are released.   
ABO mismatched platelet transfusions at least double the refractoriness rate in repetitively transfused patients (see attached for references), and actually increase bleeding and mortality. 
The answer to the question is ABO identical is by far most effective and safest.  If you have to give ABO mismatched, there is probably no good answer other than washed/volume depleted O's, A's or B's, where most of the incompatible plasma is removed.  If that's not possible, postponing platelet transfusion until ABO identical is available when feasible, giving half doses of ABO identical if two patients need the one available unit, etc. are also reasonable.
Sadly, ABO mismatched platelets are probably worse than no platelets at all. They provide little or no hemostatic benefit and increased risks of bleeding, organ injury and death for the patient.  If I were the attending physician, I would generally give no platelets if ABO identical or washed O's weren't available in a stable, non-bleeding patient with a count of over 5,000.
The good news is we can improve outcomes by just doing what we do for red cells. Do not transfuse ABO incompatible antigen or antibody. It's bad for red cells, platelets and endothelial cells, all of which have complement and Fc receptors that bind immune complexes, and all of which bear ABO antigens on their surfaces.
Carr ABO mismatched refractoriness copy.pdf ABO story expanded.docx ABO endothelial cell paper.docx NEJMc2034764 copy.pdf NEJMc2034764_appendix copy.pdf

Are you looking for reconstituted RBC from AS3 or AS1 when adding FFP? Or are you switching to using actual whole blood?  Here's a list with CPDA-1, AS3 and AS1 final product codes when you reconstitute with thawed FFP, FP24 or RT<24hr Frozen <24hr.
Starting RBC Product Code
Reconstituted RBC Product Code
 
Starting RBC Product Code
Reconstituted RBC Product Code
E0224
E5797
 
E4532
E7651
E0226
E6453
 
E4533
E7652
E0332
E6128
 
E4538
E6147
E0336
E6786
 
E4539
E6791
E0379
E6148
 
E4540
E6792
E0382
E6785
 
E4543
E6788
E0420
E6149
 
E4544
E6789
E0424
E6787
 
E4545
E6790
E0661
E6796
 
 
 
E0668
E6797
 
 
 
E0678
E6793
 
 
 
E0685
E6794
 
 
 
E0686
E6795