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Malcolm Needs

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Everything posted by Malcolm Needs

  1. Good luck with your course if you don't read around the subject. I am certain you will pass with flying colours.
  2. Sorry, but no. Mother's who have a weak D phenotype can, VERY rarely, produce an alloanti-D, but if they have a partial D phenotype, they are automatically classified as D Negative (unless they are Partial DIII, in which case, unless genotyping is performed, it is impossible to tell, as ALL monoclonal anti-D reagents react strongly with red cells that are partial DIII).I see that you are an SBB student. From this, I deduce that you either work in the USA, or follow their guidelines, and so, no doubt you will have read Sandler SG, Flegel WA, Westhoff CM, Denomme GA, Delaney M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD. It’s time to phase in RHD genotyping for patients with a serological weak D phenotype. Transfusion 2015; 55: 680-689, and the recent update Willy A. Flegel, Gregory A. Denomme, John T. Queenan, Susan T. Johnson, Margaret A. Keller, Connie M. Westhoff, Louis M. Katz, Meghan Delaney, Ralph R. Vassallo, Clayton D. Simon, S. Gerald Sandler. It's time to phase out “serologic weak D phenotype” and resolve D types with RHD genotyping including weak D type 4. Transfusion 2020; 60(4): 855-859, which will show you that, what you have said is wrong, vis-a-vis maternal D typing.
  3. I have cited this reference over and over and over again. Sachs UJH, Röder L, Santoso S, Bein G. Does a negative direct antiglobulin test exclude warm autoimmune haemolytic anaemia? A prospective study of 504 cases. British Journal of Haematology 2006; 132: 651-661, and it refers to transfusion reactions too.
  4. I would certainly think in terms of a full crossmatch, BUT using a clotted sample, just in case. That experience in the UK, although not my own, shook me up a bit!
  5. I can't refresh your memory, but I do know of a case of anti-Vel in the UK that caused a fatal transfusion reaction. The DAT was positive by anti-complement only, and the anti-Vel itself could only be detected in a clotted sample, not in an EDTA sample.
  6. Sorry, you must be fed up with me. I know I am like a dog with a bone, but, although IgG is a monomer antibody, it does have a valency of two, which is why, occasionally, it can cause agglutination visible to the naked eye. Notably, some examples of IgG anti-D cause agglutination at 37oC with D--/D-- red cells, with no potentiator.
  7. Strange. The Direct Antiglobulin Test has been around since 1946, and this is the first time that I have heard that IgG antibodies will NEVER cause agglutination to the naked eye. IgG ABO antibodies cause agglutination visible to the naked eye all the time, as do many examples of IgG anti-M and other specificities. Sorry, but I rather think you could be wrong here.
  8. The NHSBT decided to go over to National Standard Operating Procedures, and that these should be "computer only"; so, apart from the SOP's being so generic as to be completely useless to man nor beast, I asked what would happen if the computer went down, and we had to perform a procedure that was unusual, such as a DL Test. I was told that the country was divided into three areas (computer-wise) and that we could contact one of the other two for the SOP, but all three going down at once would NEVER happen. Guess what happened about three weeks later? While I don't agree with everything being kept as a paper record, certain SOP's that are rarely used, and up-to-date antibody records (given that, for many hospitals, this would not be onerous, are exceptions.
  9. Do you know, I wondered if it was you. Glad to see you back. We need people like you.
  10. There is no such thing as anti-Du. Therefore, there cannot be blood that is Du positive. Some individuals who have a normal RHD gene express a weaken D antigen because of the "Ceppellini effect" of having either a RHCE*Ce or a RHCE*CE gene in the trans position (see Ceppellini R, Dunn LC, Turri M. An interaction between alleles at the Rh locus in man which weakens the reactivity of the Rh0 factor (Du). Proc nat Acad Sci, Wash 1955; 41: 283-288), but such individuals are still not Du positive.
  11. Certainly the blood supplied by the NHSBT that what is on the label on the outside is GUARANTEED to be what is actually in the bag, and so no retyping is required. I THINK the same applies in Scotland, Wales and Northern Ireland, although am happy to be corrected. As all such "kills" would be reported to our regulatory authorities, and published in the annual Serious Hazards of Transfusion (SHOT) Report, I can say for certain that no "kills" have been reported for many, many years!
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