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Last Wash run in parallel with Eluate


simret
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Can you share with me what you are doing at your institution whether you run the last wash of an Eluate testing with Eluate? When do you run the last wash if you did not run it concurrently with the Eluate, and why? I have always run both last wash and Eluate side by side, but then I moved to a new institution, and the last wash does not need to be run in parallel with the Eluate. The Eluate would be tested; if one cell comes positive, the last wash would be tested against the last wash to ensure it does not react. This process is not efficient working in a busy Blood Bank.

Thank you for your input!!

 

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I agree entirely that this process is not efficient working in a busy Blood Bank, or any other sort of Blood Bank.  There a re many occasions when a patient can wait for the next transfusion, whilst various tests are performed, but we, as Technicians/Biomedical Scientists (or whatever else we are called around the world) are not in a position to "call the odds".  We MUST react quickly.

Granted, most of these tests will be "false alarms" (or so I would hope!), but when the test is genuine, it is necessary to react quickly.  The clinician needs to know, and so does the person working in the laboratory - THEY have got to get antigen negative blood available pretty damn quickly, while the clinician is sorting out the acute haemolytic transfusion reaction.

If it is a query delayed HTR, given that in most cases the patients are transfusion dependent (and, therefore, venerable - or even vulnerable!), why take the risk?

Edited by Malcolm Needs
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I have always run the eluate and last wash in parallel, but the question did make me think.

I appreciate the attempt to reduce (potentially unnecessary) work, but don't like the idea of doing two-stage testing (eluate first and then Last Wash, or the other way around). If this happens, you've lost any efficiency (and time) you believed you gained by not testing the eluate and Last Wash in parallel. However, the cautious approach to a low volume (rare) specimen may have some merit - checking the Last Wash first adds confidence that any eluate prepared from the washed cells will be more likely to be valid.

The two-stage testing concept has crept into the laboratory over the last couple of decades and is completely valid for follow-up or reflex testing. But.....one of my peeves: Reagents that suggest "Immediate spin, incubate negatives". If you're running a negative control anyway and/or most of your tests will be negative (DATs with anti-Complement reagents), you'll almost always be incubating, so why bother with the Immediate Spin ?

Bottom line: Do what the eluate kit manufacturer says (unless you've validated otherwise).

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I suggest to my techs during training that it may be prudent to test the last wash before preparing the eluate - especially when additional red cells are not available.  I'm sorry to report that I have seen several elutions where the last wash never became negative..... usually with cord cells where the mom had a VERY strong antibody - even changing tubes with every wash. I'm sure that if I had had the patience and persistence, it might have become negative but I gave up at 10 washes.

 

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On 9/10/2021 at 3:09 PM, applejw said:

I suggest to my techs during training that it may be prudent to test the last wash before preparing the eluate - especially when additional red cells are not available.  I'm sorry to report that I have seen several elutions where the last wash never became negative..... usually with cord cells where the mom had a VERY strong antibody - even changing tubes with every wash. I'm sure that if I had had the patience and persistence, it might have become negative but I gave up at 10 washes.

 

At that point, you could probably test the Last Wash for specificity !!:) You'd probably get the results you need.

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