IS XM Positive-Next Step?

[REN_NH]

If a patient's Immediate Spin Crossmatch is weakly positive (tube method), and the Antibody Screen and IgG Crossmatch (GEL) are negative, what is the next step to prove Blood Type compatibility? Advancing to pre-warmed method seems a waste of time since the GEL Crossmatch is already negative.

[John C. Staley]

My next step would be to pull another unit off the shelf and see if it is IS compatible.  The problem may be with the unit and not the patient.

[REN_NH]

Let's assume all units are reacting the same way due to a cold antibody.  What needs to be done to deem the units ABO type compatible?

[John C. Staley]

21 hours ago, REN_NH said:

Let's assume all units are reacting the same way due to a cold antibody.  What needs to be done to deem the units ABO type compatible?

So, is this then not a real and current situation but instead an exercise in, what if? 

Why would pre-warming be out of the question if you are already convinced that the antibody screen is negative and all you want to do is confirm ABO compatibility?

[jshepherd]

If the reactivity is only in the IS phase, and all other IgG phases are clear, you should do the things to resolve IS interference. If you can identify or think there is a cold antibody, then prewarm would be your answer. You can also wash the donor cell suspension to ensure there isn't something funny with the patient's plasma and the unit anticoagulant or solution. 

[Yanxia]

On 12/22/2023 at 1:09 AM, REN_NH said:

Let's assume all units are reacting the same way due to a cold antibody.  What needs to be done to deem the units ABO type compatible?

Maybe repeat ABO typing can prove it.

[Texas Tea TMC]

3 common interference possibilities

Rouleaux - look at the reaction under scope, see if you see the coin stack appearance. Resolve IS interference with saline replacement

Nonspecific cold agglutinin - perform mini cold screen   - one group O big I+ adult cell (screen cell works fine), one group O i cell (cord blood), and autocontrol. 2 drops patient plasma to each of those cells.  Read at IS, RT inc and 4C inc. If autocontrol and adult cell are positive, and reactions increase in strength with refrigeration, its usually presumptive nonspecific cold agglutinin. Resolve with prewarming the plasma to reduce interference at IS phase. May not work if cold agg is strong.

Cold preferring IgM antibody like an Anti-M or P that doesnt show in gel but may interfere in tube if the crossmatched unit is antigen positive.  Run a 3 cell tube screen with IS phase and a RT phase to get clean strengths to id the antibody. Your hospital policy should specify whether you need to antigen type units to get real crossmatch compatible, or just crossmatch untyped units until you get a IS XM compatible one. Most hospitals consider the common suspects (M, P, Le) not clinically significant if they are only showing at IS, but if you work at a place that requires IS XM on all rbc orders, and they want it "compatible" you might be stuck antigen typing.

And lastly always a chance the unit or patient ABO result is incorrect, repeat the ABO typing on patient sample and unit.  

  

[REN_NH]

Thank you all for your kind responses!

Does anyone use Blood Warmers any more for cold agglutinins or is that reserved for MTP and pediatric transfusion to minimize hypothermia?

We do retype our donor units and perform a second type on our patients, but as a workup for this specific case, I think repeating again to remove all doubt would be a good idea, especially since it may not have been the same tech performing the original testing as for the crossmatching.

We use Meditech and have the capability to say "Least Incompatible" as a work around for the common not clinically significant cold Ab's. I would just have to include the specifics in our policy. 

We also do saline replacement.

We are a small Critical Access hospital with the nearest ARC Reference Lab 3 hours away but I think the mini cold screen may be doable for us Generalists.  

 

Happy Holidays!

 

[Texas Tea TMC]

Our blood bank maintained warmers go out mostly to

1)people who are having clinical symptoms from their colds (autoimmune hemolytic anemia with activity at IS/RT, PCH/PNH).

or 2) patients with colds causing significant interference in multiple phases of testing.  Not just minor ABO mismatch that can be resolved, but strong reactions where the screen isnt negative initially either. REST x4 patients with grossly hemolyzed plasma, that kind of problem.  

ER/OR/ICU maintain their own blood warmers for use with patients having multiple unit transfusions fairly quickly. 

[Melanie Oliveira]

You can't use REST adsorbed plasma to XM.  IT removes ABO iso hemoglutinins.  But use your validated computer system if all else fails.   If your computer is validated and will not let you select ABO incompatible units then it can be used for ABO compatibility.

[Bet'naSBB]

If your patient is O, it would be hard to tell if there is a cold auto or cold reactive allo antibody present.  If your patient is A and the reverse is clear, that can R/O anti-A1 - but your reverse cells might be ag neg for whatever the person "has" so the reactivity might be as expected......same with a B patient.

we would run a cold screen with an auto control  (IS, RT, 4C).  use the reactivity for that to decide your next steps......ie - pursue a cold auto or a cold allo.

we would also run a DAT + monospecifics and if complement is positive, we would do a thermal amplitude and a cold adsorption.......but, we're also an academic medical center and our BB is as close to being a reference lab without being a reference lab as you can get and we work up EVERYTHING!  

[jtemple]

The biggest offender in this scenario is not letting your reagents come to room temperature before testing. Waiting at least 15 minutes after taking reagents out of the fridge will avoid a lot of this. If that is not the case here, perform a DAT on the unit. 

[SbbPerson ☆]

On 12/21/2023 at 6:01 AM, REN_NH said:

If a patient's Immediate Spin Crossmatch is weakly positive (tube method), and the Antibody Screen and IgG Crossmatch (GEL) are negative, what is the next step to prove Blood Type compatibility? Advancing to pre-warmed method seems a waste of time since the GEL Crossmatch is already negative.

 

Did you try checking for rouleaux? Sometimes rouleaux can cause the immediate spin XM to be positive but the Antibody screen negative.  All you need is saline replacement to see if its rouleaux. Or look at the cells under a microscope to check for rouleaux. 

Edited December 30, 2023 by SbbPerson

[ckcheng]

Check the patient's A/G ratio and ESR give you a faster way if you suspect rouleaux.  A2 patient with anti-A1 also possible.