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exlimey

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exlimey last won the day on March 22

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    Gaithersburg, MD, USA
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    IRL; Reagent Manufacturing

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  1. exlimey

    Antibody Evaluation

    I agree with Malcolm - the IgG/IgM nature of the antibody is not relevant, and I would avoid tests with enzyme-treated cells in patients with confirmed WAIHA, especially after adsorption procedures. I know that some workers also avoid PEG when testing adsorbed serum in these cases, opting instead for LISS or even saline antiglobulin tests on the adsorbed serum.
  2. exlimey

    ABO Retype

    Short (facetious) answer: $$$$$$$$$ Long answer - my opinion - Facilities required or choose to follow AABB Standards (and therefore get an inspection) are required to pay for/buy said standards. At the very least, they are "institutional members" that pay an annual membership fee. The AABB Standards are very different from the Technical Manual (in which the universal, public domain procedures reside). I may be wrong, but I think the standards get some kind of tacit approval by the FDA, whereas the TM gets peer-review. Of course, both documents/books are available to anyone for a fee......
  3. exlimey

    PEG vs LISS

    Thank you, Johnv. I know the science.
  4. exlimey

    PEG vs LISS

    Isn't it fascinating that we're "allowed" to deliberately use a less-sensitive assay when "we" feel it appropriate? Offhand, I can't think of anything similar in other path disciplines. Anyone ? Anyone ? And..... go........
  5. exlimey

    Complement QC with Poly IgG

    My interpretation: Users of POLYSPECIFIC antiglobulin reagents are obliged to verify performance each day of use, i.e., QC should involve use of IgG-coated cells AND Complement-coated cells. This gives the user confidence that the reagent is performing as expected. During routine testing, addition of IgG-coated cells to negative tests is sufficient to verify that the IAT was performed correctly - correct/effective washing, the antiglobulin reagent was added and is reactive, etc. If it were a requirement to add IgG-coated cells and complement-coated cells to every negative IAT using polyspecific antiglobulin, it would be necessary to run everything in duplicate - one set would get IgG-coated cells and the other set would get complement-coated cells. I don't think that is the case.
  6. exlimey

    PEG vs LISS

    PEG-IAT is arguably the most sensitive tube test currently in widespread use. For this reason you're more likely to see concurrence with your Echo/Neo results if you use PEG for supplementary testing, i.e., the sensitivity of the two assays are perhaps the closest (LISS being less-sensitive). However, there's still a chance that the Echo/Neo will detect something that is not detected in PEG (or LISS). I wonder what Immucor would say if you decided to use another manufacturer's PEG reagent ?
  7. I think the term "Chav" has recently become popular. Even more recently, calling someone "a right old Neymar" is not very flattering. As the Irish writer George Bernard Shaw once said: "England and America are two countries divided by a common language."
  8. exlimey

    Cold Agglutinin incubation phases

    Wow. Thank you for that information. That certainly could influence the concern some of the medics demonstrate. Is the surgical room also chilled ?
  9. exlimey

    Cold Agglutinin incubation phases

    That is exactly the theoretical risk that concerns the medical staff, but in my non-medical, laboratory-based opinion, the risk is extremely low. Extreme testing protocols (below 30 C) for cold-agglutinins are rarely informative, often having very specious clinical relevance. Does anyone really know what the results mean ? How high must a titration be to be significant ? If you look hard enough, you can find cold-reactive autoantibodies in most people, hence why routine testing protocols now deliberately avoid test phases below 37 C. Modern, super-sensitive test systems (PEG-IAT, CAT) don't even allow tests below 37 C and openly admit that IgM antibodies may not be detected (typically the form that "colds" take). Even with these "deficiencies" they still are licensed/approved for antibody detection and ID. If a patient is in such a dire situation that they're undergoing radical surgery, with the selective use of hypothermia and/or by-pass procedures, the least of their worries is a cold agglutinin. The easy fix to the transfusion of "cold blood" is a blood warmer, but obviously this would be contraindicated during hypothermic processes.
  10. exlimey

    Cold Agglutinin incubation phases

    Perhaps I'm a little naive, but I find some of the "old time" logic somewhat illogical. I appreciate that a unit of red cells being transfused would potentially be "cold" - 1 - 6 C at the start of infusion, i.e., might cause a cold-agglutinin issue, but almost immediately, the infused portion would equilibrate to the temperature of the circulating blood. Additionally, the unit itself would start to warm-up to room temperature. Certainly additional problems could arise from "by-pass" procedures, but are the devices\pumps "cold" - 1 - 6 C ?? I suspect they operate at room temperature, nowhere close to refrigerator temperatures. After all that rambling, I meant to say that I don't why anyone would test "cold autoantibodies" at temperatures below that of typical (surgical) rooms. However, I'm sure there is a a whole library of circumstantial, anecdotal evidence supporting such extreme testing protocols.
  11. exlimey

    IgG vs AHG

    Does the MTS gel card you typically use contain polyspecific antiglobulin reagent (anti-IgG + anti-complement) or does it just contain anti-IgG ? I think most users are using anti-IgG cards, and if that is the case, they're already dealing with the "Is it possible to miss a complement binding IgM antibody early on by using IgG only." issue.
  12. exlimey

    RESt and DARA

    RESt = Rabbit Erythrocyte Stroma - basically stabilized red cell membranes from rabbits. There is absolute no DTT in RESt.
  13. I just answered this question. My Score PASS  
  14. I read on the Internet that if a person sinks in water and drowns, they're proven to be a witch........
  15. I suspect that routine use of enzyme-treated cells (in IAT) by "Non-reference Laboratory Staff" would cause more confusion than it would solve. Even the largest, most proficient hospital laboratory doesn't have high caliber serologists available on all shifts. I would suggest that tests with enzyme-treated cells be restricted to more difficult serological pictures, e.g., post-transfusion hemolysis without obvious cause (read "anti-Jka or anti-Jkb"), or for investigation of antibodies to high-incidence antigens. I also suspect that many of the "enzyme-only" specificities have a major IgM component - notoriously difficult to detect by CAT (gel). Just my two cents/pennies.☺
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