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exlimey

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Everything posted by exlimey

  1. I think you're joking, but just in case...... It's a simple C1 x V1 = C2 x V2 calculation. One of the few times when algebra gets applied outside of high school. To do this accurately, you must first know the hematocrit (concentration) of your "packed cells" - this will be used as C2. For this example, let's say the hct is 75%. C1 = desired hematocrit (concentration) - 3%; V1 = desired volume - for this example, let's say we want 100 mL of 3% cells. Using the formula and information above.... 3 x 100 = 75 x V2, which resolves to 3 x 100 ÷ 75 = 4 mL. Ergo: 4 mL of "packed cells" in 100 ml pf PBS will yield ~3% suspension. This process works for low cell concentrations where the added RBC volume is only a small portion of the whole (4 mL added to 100 mL). If you try to make higher concentrations, you have to take the RBC volume into consideration as part of the whole volume.☺
  2. ANORRIS, I think you might need a few more details in your question before anyone can lend advice.
  3. Well said, John. We've all been in positions where "extra work" was logical because either the original request was wonky or we did it for our own sanity.
  4. First step: Is it reacting with autologous cells ? Fairly easy to make that call, IF the patient is untransfused. If the patient is transfused, it gets more difficult, if not impossible. Any reasonably competent IRL should be able to help. If necessary, they would be able to perform adsorptions and/or test rare cells. They may even be able to isolate autologous cells from a transfused patient.
  5. I think Scott is saying that there is still a cost associated with each test, regardless of billing. Socialized medicine bean-counters have a very real interest in making things efficient and cost effective. Redundant or unnecessary testing is the target in such situations.
  6. The key question: Is it auto or allo ? This may be difficult to prove if the patient has been transfused. If it is an autoantibody, I agree with Malcolm's position - who cares? However, if the autocontrol is nonreactive, you may have to consider other things. Beware anti-Vel and anti-PP1pk (-Tja). These can behave like cold-reactive AUTO antibodies, i.e., demonstrate panagglutination, abolished reactivity by pre-warmed tests, etc. There is at least one case (published by Jill Storry) of an anti-Vel that was "dismissed" as a cold auto (it was rendered nonreactive by pre-warming). The patient was transfused with random cells and had a fatal hemolytic reaction.
  7. I would check the regulations VERY carefully. I suspect it would be very difficult to make this kind of thing mandatory, especially if there is some arbitrary cutoff (transfusions/yr). On the other hand, if your boss would LIKE you to participate, it might take some clever moves to convince them to decline. Good luck.
  8. A serious finger wagging ????? Twelve lashes with a wet noodle ????? A stern, disapproving look ?????
  9. Perfect ! Throw in a risk of workers' comp. and the argument is won quickly. Nicely played.
  10. I agree too. I find it additionally perplexing that that information from these types of surveys usually takes a few years to be compiled and published. Not much use after the fact.
  11. Fascinating.....voluntary, but, it appears, strongly encouraged. I wonder in how many institutions this has been translated to "mandatory"? I lean toward R1R2's position - don't do it, especially if it is indeed a "doozy" or a "stinker". We're all busy enough already. Unless the survey organizers (FDA) are going to provide funding for such an exercise......
  12. While it is not impossible, it can be extremely ticklish to extend an expiration date (of anything) beyond that of the manufacturer. You may find that the burden of proof required exceeds the value of the theoretical savings. You also have to remember that the manufacturers of the products put on that expiration date for a valid reason - presumably their testing indicated some deterioration/deficiency over time. Certainly microbial contamination is an issue and culturing may provide useful data. However, and this is a BIG HOWEVER, most BB saline products do not contain preservatives and don't claim sterility after opening. Therefore, you will undoubtedly end up at some point with positive cultures on opened containers. The question then becomes "How much contamination can our test system tolerate ?" - a very difficult question to answer satisfactorily. Perhaps more importantly for BB testing is stable pH and any plan to extend the expiration date of saline should include pH testing.
  13. One presumes that the FDA know what they want you to do. Perhaps you should ask them......? I know, my advice is not very enlightening, but second-guessing what hoops the regulatory agencies want you to jump through is an exercise in futility.
  14. I'm sure you sent them a card.......
  15. I agree with the sentiments above. Wiggle room is always a good idea when creating ranges for any activity/process. The art is in defining the range - certainly you don't want to be too strict that an unexpected event throws you out-of-compliance. Neither do you want ranges that are so broad that they are effectively meaningless. For maintenance, a good idea is to have a target date and then add your wiggle factor (+/- days, weeks, months, etc).
  16. An excellent idea ! No need to re-invent the wheel.
  17. No worries, perhaps I was just a little sensitive. May I presume that your detailed knowledge of the reagents and platform (and the Swiss flag) is a result of an association with the company (formerly know as DiaMed) ??
  18. No need to get so snippy. Unlike you, I am not intimately familiar with the state of things in the UK - that's why I asked.
  19. Food for thought: Are the reagents licensed/approved for use on the instrument ? If "Yes", then minimal validation is required (and is perhaps better called "verification"), but 10 samples is probably too small (even if you select/cherry-pick the phenotypes). You would have a very hard time covering all of the most common Rh haplotypes/phenotypes with such a small sample size. If "No", then you're definitely in the validation realm and 10 samples is way too small to achieve appropriate statistical confidence levels. If you have a pet statistician, it might be worth talking to them. BTW, if the phenotypes of the selected test samples are already known, there is no need to re-test them manually as part of this process. As Malcolm suggests......there are some not-so-secret ways to collect that information. A final brain-dripping: You will need a plan to deal with discrepancies. No two techniques are the same, nor are the formulations of the reagents (monoclonal cell lines and other secret ingredients).
  20. I was wondering if the probe was able to be moved, but probably not. I'm sure the manufacturers don't want the end users monkeying with their delicate electronics. If the probe could be moved, it might be possible to angle it into liquid nitrogen (LN2) - that would set off the low/cold alarm ! That's what we do in my facility, but our probes are accessible/flexible enough that we can move them around fairly easily. May I assume that you're only doing a one-point calibration/certification of the freezer probes ?
  21. How do you calibrate or verify calibration of your freezer temperature probes ?
  22. Patty, you may be getting your markers mixed up. Daratumumab reacts with CD38 (not CD47). It is an IgG1 antibody and reacts nicely with Immucor's reagent.
  23. Who's responsible for training and tracking, etc. - nursing or the Blood Bank ? How does one know that the body that turns up to collect the blood has been trained ?
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