Warm Auto Workup Frequency

[Everett9239]

We have many patients in our population that have warm autoantibodies.  Most of the time, we try to get a phenotype on them, or have molecular genotypes done to provide phenomatched units.  That being said, on the patient's that we are able to provide these type of units for, there is a question concerning how often they should have their warm auto 'worked up' to make sure there is nothing underneath?  We are transfusing these patients, but in theory they should not be stimulated to make any other antibodies.  I guess I just want to take a poll to see what the rest of the world is doing.  Currently, we are using an every 30 day rule.

[Terry Butler]

We treat our warm auto patients the same as all the rest. New samples are worked up every three days, regardless of whether or not they have been transfused. Exceptions are cleared by our pathologists.

[Likewine99]

Same as Terry

[tbostock]

For warm autos that have been sent to a reference lab, and we have a phenotype, and we are giving phenotypically matched units, we still do the T&S every 3 days, but we do no further workup unless we see a significant difference in the strength of the reactions, specifically the DAT result.

 

We do AHG crossmatches on the phenotypically matched units, they are incompatible anyway due to the warm auto interference, and we have the MD sign for incompatible units.  And we have pretty strict transfusion criteria for warm autos (lower hemoglobin and symptomatic).

[BankerGirl]

I have been wondering what value there is in crossmatching units through AHG when the patient has a warm auto antibody that is reacting with all cells.  I know that some facilities use the adsorbed plasma to perform their crossmatches, but that doesn't seem right to me, since that isn't what the patient has circulating.  This seems like a lot of unnecessary work, knowing the patient will be incompatible and the physician will have to sign the incompatible form.  Does anyone actually not crossmatch these units?

[Malcolm Needs ☆]

Not in the UK.  We may cross-match by "immediate spin", but only after we have performed the alloadsorption and "proved" that there are no underlying alloantibodies.

 

I put "proved" in quotation marks as, of course, the alloadsorption cells will remove any antibody directed against a high prevalence antigen (such as Vel) that is not sensitive to papain (we always use papain-treated red cells for the alloadsorption, as they adsorb more effectively than do untreated red cells.  The units are always issued as 2suitable", rather than "compatible" for this reason, with a warning that observation during transfusion is "even more" paramount (if that isn't an oxymoron, I don't know what is!!) than normal.

 

Actually, come to think of it, there will be rare occasions when we cannot fully adsorb out the auto-antibody, in which case we would recommend giving ABO, Rh and K matched blood and, if the auto-antibody is a "cold" auto-antibody of wide thermal amplitude, even an "immediate spin" cross-match may not be compatible, but this is indeed a rare situation.

[Mabel Adams]

The only reason to use adsorbed sample in an AHG xm is to detect underlying alloantibodies to a low frequency antigen on the donor cells that might not have been detected when doing a screen or ID on the adsorbed sample.  Considering all of the other leaps being taken when transfusing these patients I doubt that many could justify doing the xm.  I suspect some want to put a label of "compatible" on the units, but not me, since the units will be incompatible with the autoantibody in vivo.

[Malcolm Needs ☆]

I sort of agree with you there Mabel.  You certainly will not detect anything in the panel that you would not detect using screening cells.  However, so many times we see reactions against, for example, the R₁R₁ and rr screening cells, against the plasma adsorbed with R₂R₂ cells, which means that we then have to go on to prove that the reaction is due to an auto-anti-e (or, more likely, an auto-anti-e-like antibody) that has not been adsorbed out by the R₂R₂ cells, meaning that we have to perform a panel to prove this, that we just throw our hands up in submission and perform panels anyway.  We are "savvy enough", however, to perform the panels with selected cells, rather than the full panel.

 

I totally agree with your final point.

[Mabel Adams]

 We are transfusing these patients, but in theory they should not be stimulated to make any other antibodies.  

I believe I've read that patients with warm autoantibodies are MORE likely to make alloantibodies after transfusion than are patients who don't have autoantibodies.  Their immune system is operating in a heightened state.  But perhaps you mean they won't be sensitized because you are giving completely phenotype-matched units, not just Rh and K?  

[BankerGirl]

So Malcolm, do I understand you correctly and you perform an immediate spin XM with no AHG XM? 

[Malcolm Needs ☆]

Yes BankerGirl, we do have that option in our SOP, although it is quite rare that we use this option.

[BankerGirl]

Yes BankerGirl, we do have that option in our SOP, although it is quite rare that we use this option.

So back to my original question, what is the value of performing an AHG crossmatch when the plasma reacts with all cells tested?  In what circumstances would you just do an ISXM?  It seems that this is nothing more than busy work and extra charges to the patient who already has a humongous bill due to all the work required to exclude any allos.