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David Saikin

A Little Help Please

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Interesting study but I could use another brain.

Last evening:

Pt presents w a broken wrist.  Looks like an A+ (R1R1) except the reverse A1 cells are mf (gel).   Antibody screen all mf except auto.  A2 cells and M= cells: all mf.

Cold autoabsorption:  results the same.  Strict prewarmed using tubes/PeG/anti-IgG:  all are 1+ except auto (neg).

PeG Autoabsorption:   all cells negative.

I want to assume a cold etiology due to the reverse grouping discrepancy.

Patient was discharged before additional samples could be obtained.  No medication history and no PCP documented.

Any thoughts out there please?   I have about 4 drops of plasma remaining.

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DAT performed?  Neg autocontrol does not always equal a negative DAT.  How strong was the mixed-field and was the antibody screen in tube or Gel?  PEG prewarm in tube not mf?

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Gel mf is top and bottom.  1+ (in tubes) is always mf by definition.  DAT negative.

All testing is gel except for the PeG testing.

Edited by David Saikin
more info

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Hmmm....   Not too fond of PEG adsorptions; did it truly adsorb the antibody out or was the antibody lost in the precipitate?  Pondering if you have two different things happening:  Rouleaux in your reverse (I'm assuming the reverse typing with the A1 and A2 cells was not 3+ or 4+....were the majority of the cells at the bottom or top?)  and Gel testing with an alloantibody in PEG?  With 4 drops of plasma, you could eliminate the rouleaux as an issue.

Thinking out loud....negative DAT, negative autocontrol usually does not equal an autoantibody (one of the reasons I'm cautious about the PEG adsorption resullts), although it is well known that "antibodies don't read books".  In the tube tests, how strong was the initial spin prior to adding the PEG?

I know I'm reaching a bit on the rouleaux, but I have always found it beneficial to not overlook the simplest explanation before moving on to the more obscure.  Is there any additional sample in hematology that you could play with? 

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Repeated DAT in Gel  1+w.  Makes me feel better.  Cannot resolve the reverse grouping results.  I played with both specimens (as did the evening folks).  The mf results in gel were pretty equal as to top and bottom.  I only did prewarmed w PeG so no immediate spin.

Elution is a 4+ panagglutinin in gel.   Doesn't look like rouleaux.

I think the Peg absorptions work nicely (have done many).

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Auto directed at senescent red cells can show mixed-field reactivity.  With your additional information, kinda seems the most likely cause of your observed reactions.  Garrartty and Petz discuss this in Immune Hemolytic Anemias, 2nd ed., pg 243.

The issue with PEG adsorptions is they may work too well, potentially resulting in the loss of weak (low titered) antibodies.  Of course, that could happen with any adsorption, I guess, but with the samples we see in our ref. lab, it is the last technique we would use to adsorb out an autoantibody.  I'm not saying you are wrong to use it.  I'm just saying it has it's drawbacks;  

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17 hours ago, StevenB said:

 

The issue with PEG adsorptions is they may work too well, potentially resulting in the loss of weak (low titered) antibodies.  Of course, that could happen with any adsorption, I guess, but with the samples we see in our ref. lab, it is the last technique we would use to adsorb out an autoantibody.  I'm not saying you are wrong to use it.  I'm just saying it has it's drawbacks;  

I understand but in a 20 bed hospital it works just fine.   You also run into the issue which perplexed me for a while.   Weak gel rxs are invariably negative in tubes no matter what enhancement you use.

Edited by David Saikin
more thought

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6 hours ago, David Saikin said:

I understand but in a 20 bed hospital it works just fine.   You also run into the issue which perplexed me for a while.   Weak gel rxs are invariably negative in tubes no matter what enhancement you use.

In my experience, the two most common causes of weak reactivity in Gel and negative reactions in tube are either rouleaux (no, not my pet "go to", but still applicable) or reactivity seen only with the manufacturer's prepared 0.8% reagent cells.  We encounter this fairly routinely:  Hospital gets Gel reactivity, sends it in, we do a selected panel making our own 0.8% suspensions from various manufactures, get a negative Gel test, test with a manufacture's 0.8% panel and get reactivity.  Basically, reactivity dependent upon something in the manufacture's product.  Kinda similar to a "LISS panagglutin".

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Seems as  warm autoantibodies which have a  loose reaction temperature span, so they can interfere with the reverse typing. Because they are not cold auto, so cold autoadsorption does not work, and in the strict prewarm test, they still react.

 

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On 1/24/2020 at 3:42 AM, David Saikin said:

Repeated DAT in Gel  1+w. 

I have a little confusion, why the previous auto tests are all neg, and the DAT is pos? The elution result is 4+, so I guess this DAT is IgG pos, and the  anti-IgG in the prewarm test, the auto is neg.

My not good English, I hope I understand and express it right:lol:Sorry for the interruption.

Edited by yan xia

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Has the presence of anti-Sda and anti-Lub been ruled out? Both have been reported to show mixed field reactivity and both can be reactive at room temperature. Microscopic exam of reactivity in any phase would help rule out anti-Sda, and since your said it did not look like rouleaux, can it be assumed that it also did not look like an anti-Sda? That leaves possible anti-Lub.  The RBCs could be cleared of IgG and typed or an Lu(b-) RBC could be tested with serum and eluate. And, this could be an autoantibody...And then going back to a sample to blood bank for broken wrist, perhaps more going on diagnostically here, What was admission Hgb? Transfusion history is important for auto vs allo specificity. With the eluate stronger than the serum and with mf in DAT, should be concerned about possible transfused cells and this being an alloantibody.

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