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exlimey

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Everything posted by exlimey

  1. exlimey
    Wow, David, you must live a charmed life if you haven't been tripped up by "bad" saline sometime in your career. Certainly in the vast majority of cases the actual pH of saline has little impact, but there are lots of examples where changing the pH of a test system has deleterious effects. Most manufacturers of blood bank reagents and test platforms now specify pH ranges for saline, essentially requiring the use of buffered saline.
  2. exlimey
    You were unlucky tripping over an antibody to a to a low incidence antigen. Sometimes the fancy commercial panels are too fancy. Some of the antibodies to low incidence antigens are quite common and only remain undetected because regular red cell panels do not have the corresponding antigens. In this situation, I would make every effort the get a blood sample from the putative father - a sometimes awkward and emotionally-charged situation. Test the father for Dia (and E while you're at it) and if negative, you don't have to continue to evaluate the potency of the antibody(ies). Getting a sample doesn't always work, of course and there's always a risk that the "father" is not THE father.
  3. exlimey
    A valid position, BUT, how often is such a large discordance seen ? Probably not often. I'm sure there are statistics out in the ether somewhere. Perhaps storing the previous sample, or series of samples would be useful - this would allow a logical investigation of any anomalous results. Repeating the titration every time is extra work and in most cases, of little value.
  4. exlimey
    While I agree that parallel testing of a previous sample and a current sample will potentially even-out the intrinsic variation in antigen expression of test cells, I would hope that a well-trained cadre of operators following a good SOP would get the same titration results (end-point) when testing the same sample time after time. A vague, musty memory suggests to me that there are proficiencies along those lines - independent samples to be titrated, tested and the results reported. Perhaps that has gone the way of the dinosaurs?
  5. exlimey
    And in the examples you suggested - probably with the strategic application of some chemical and/or exotic enzyme treatments. Totally out of control. Scandalous!
  6. exlimey
    I really only responded so that I could smash more light bulbs.........
  7. exlimey
    I'll put my Malcolm hat on: That's a red cell panel, not an antibody panel.☺
  8. exlimey
    Disturbingly addictive.....
  9. exlimey
    I wouldn't worry about the possibility that the auto/allo antibody is Ce. Since the patient is Rh-negative (rr), any transfusions would also be Rh-negative - the very great majority of which are also C-. Only a very small chance of finding a random r'r in your D- donor pool, not impossible, but remote. I agree with Malcolm - hyperhemolysis (US spelling). These folk have wacky immune systems anyway and the massive dose of foreign antigens delivered by a transfusion can cause them to react in strange ways. Earlier workers used the term "bystander hemolysis". I understand that even with very low hemoglobiin levels, avoidance of transfusion in these persons seems to be the best practice.
  10. exlimey
    Thank you, Cliff. That's very interesting. I was wondering if you planned to do comprehensive phenotyping, and you are. One comment: Super-strong, FDA-licensed reagents may not allow detection/demonstration of weakening of antigens. Perhaps a better way to detect weakening of antigens would be to use a weak and/or diluted reagent. You could even do comparative titrations and add up scores....
  11. exlimey
    Cliff, If you wouldn't mind, please explain what you are validating - not specifically how, but what elements are you evaluating.
  12. exlimey
    I see your point SMILLER/Scott. It's a fair argument. I'm not advocating "less oversight", but merely acknowledgement that an immunohematology work-up often has a lot more "grey/gray" than the other pathology disciplines. As we all know, "antibodies don't read books" and sometimes it takes all of your resources and experience to resolve a serological problem, including the prudent use of expired materials (or frozen inventory). One could argue that absolute prohibition of using expired reagents in such cases could potentially put a patient at more risk by leaving an issue unresolved. Using all of your tools, in-date or otherwise, to get a good answer might outweigh the regulatory implications. As I alluded to earlier......I don't recommend front-line techs use expired reagents willy-nilly - they should be used surgically and by those skillful enough to recognize the limitations.
  13. exlimey
    Sometimes I think that the "regulators" feel obliged to fix problems that don't exist. Does anyone recall a rash of patient morbidity/mortality due to the use of expired reagents in the blood bank arena? That being said, the use of such material should be restricted to those with the appropriate knowledge and expertise.
  14. exlimey
    Enzyme-treated cells can be very useful in the hands of expert serologists who know the pros and cons of their use. Routine use by front-line techs is probably ill-advised. In this case, some level of feasibility testing might be useful before switching to an enzyme-treated panel, but I would hesitate to call it "validation". Each facility should determine if such a panel is useful to them, or if it would cause more problems that it would solve. As I mentioned in earlier in this thread - I believe these are FDA-license reagents and they do not require validation.
  15. exlimey
    My personal opinion - no validation required. You are switching from one FDA-licensed product to an equivalent. Unless you plan to use it in a fashion contrary to the manufacturer's instructions it's a business decision rather than one of quality or performance. If you have an internal policy that directs you to "validate" in these situations, you should change that policy. Anything that an end user does to "validate" a commercial, FDA-licensed red cell panel is dwarfed by the process involved to get these products to the market. Perhaps more important is that the replacement product suit your facility's specific needs. The typical antigenic make-up of the panel you select should reflect your particular testing requirements. For example....if you have lots of patients with anti- D, a panel with lots of D+ cells my not be very useful.
  16. exlimey
    Couldn't agree more. Any time you start messing with samples you have the chance for mix-ups. Sounds like a bad idea.
  17. exlimey
    Interesting question - do rabbit red cells carry CD38 ? I thought I heard/read that removal of anti-CD38 by adsorption was not successful using human cells (which we know carry CD38). Even if rabbit red cells do carry the marker, I assume the same would apply ?
  18. exlimey
    Jealous.........
  19. exlimey
    An interesting position; in practice, it would probably work fine. I am not a regulatory expert, but I thought that both IS crossmatches and electronic crossmatches are only permissible after a negative antibody screen. Obviously in the DARA/anti-CD38 cases this would not be so. You may be able to wordsmith your way around the constraint.
  20. exlimey
    I stand corrected, maybe.
  21. exlimey
    Since your patients are NOT getting regular transfusions, I would hesitate to get full genotypes. If they switch over to being regularly transfused, it might be worth reconsidering, but you may paint yourself into a corner and find it necessary to "honor" the other DTT-sensitive antigens like Yt and Do. See DargonLady's comments above. A K typing can be easily performed using monoclonal antisera, even after the first dose of drug and if the DAT is positive.
  22. exlimey
    Since it has been reported that workers are unable to remove anti-CD38 by adsorption, I suspect that one would be unable to elute said antibody, rather similar to "HTLA" antibodies. An eluate could be free of anti-CD38 and therefore be testable, however, there are hundreds of reports of nonreactive eluates in patients with obvious hemolytic and/or serological transfusion reactions.
  23. exlimey
    What do you mean by "validated" ? Have you actually validated your ABO grouping process?
  24. exlimey
    I'd like to be a fly-on-the-wall when you have that conversation with an Inspector......just kidding. I suspect many folks are doing just as you describe and for the same reason.
  25. exlimey
    As Malcolm points out, washing is not really important for ABO grouping in the modern era of tube testing. The reagents are formulated to tolerate a degree of neutralization. I assume this is true also for the reagents used in gel cards. Washing is important when using the cells in any test using antiglobulin reagents (as LIMPER55 notes). Perhaps more of a concern is that your in-house procedures should not contradict the reagent manufacturers' instructions. One could even argue that an SOP is not really required if you follow the package insert - that's your SOP! Whichever approach you take, you should definitely be following your SOP. I can see and hear the regulatory folks cringing in their seats as they read your post.
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