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Showing content with the highest reputation on 09/21/2021 in all areas

  1. It would be really useful if you could tell us the ethnicity and age of the patient, and his medication regime. That having been said, I note that the antibody screen is positive, that his DAT is positive by both anti-IgG and anti-C3d, that the neat plasma contains an apparent anti-E and anti-c, but that the eluate contains an antibody that is, apparently, pan-reactive. Very often in these cases, the apparent antibody specificity in the neat plasma is a mimicking specificity, rather than a true specificity. In such cases, the apparent specificity in the neat plasma can be adsorbed out using red cells that are negative for the antigens of the apparent specificity; in this case R1R1. The true specificity of the antibody could be an anti-Rh17 or anti-Rh18. While I am not saying for a single second that the apparent specificities of anti-E and anti-c are not true specificities, it may be worth your while seeing if they can be adsorbed out using R1R1 red cells. However, as you suspect the presence of other antibodies, this should not be attempted until you have proved otherwise. This you can do, as you suggest, by alloadsorption of the neat plasma using two or three adsorption cell types. In answer to your last question, with regard to adsorption of the eluate, this was certainly a method we used in the Reference Laboratories of the NHSBT in the UK. It was usually used when the patient had a known pan-reactive autoantibody, but was requiring transfusions more frequently than previously, and/or when the expected rise in the haemoglobin concentration was not achieved. On some occasions, we were able to detect a de novo alloantibody in the eluate that we could not detect in either the neat plasma, or the adsorbed plasma, although this was not always the case, as transfusion in and of itself can sometimes stimulate the autoantibody to become more active (see Petz LD, Garratty G. Immune Hemolytic Anemias. 2nd edition, 2004, Churchill-Livingstone). Good luck with sorting it out, but this is a really interesting case. Thank you for posting it and, please, would you mind letting us know how you get on?
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  2. 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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  3. Run side by side. Does your SOP, or manager (or anybody for that matter) give a reason why it is eluate first then Last wash? It would make more sense for a policy to state run the last wash prior to the eluate (especially if there are few red cells) to ensure sufficient washing.
    1 point
  4. 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?
    1 point
  5. I don't know if this will help or not. I talk a bit about anti-D prophylaxis towards the end, and why it sometimes fails. If it doesn't help, just ignore it!!!!!!! In Depth Lecture on Alloimmune Haemolytic Disease of the Foetus and Newborn HDFN.pptx
    1 point
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