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galvania

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galvania last won the day on April 29

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About galvania

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  • Birthday 05/09/1955

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    Jazz, birdwatching, gym
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    Castelletto di Vernasca, Italy
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    ex teacher/BMS in transfusion science. Now retired

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  1. 1. did you think to do a DAT on the posttransfusion sample to see if the antibody was all 'stuck' on to the transfused red cells? 2. What method did you use to K-type the units of blood? did it involve an IAT? If so was the positive result a false positive because the unit had a positive DAT?
  2. sorry for the late reply. What I meant is that one tends to put up a batch of antibody screens. In the time taken to put up say 12 screens the cells can cool down enough for a cold anti-M in the plasma to latch on. On the other hand, panels tend to go up one at a time (1 patient at a time) so cells have less chance of cooling down. (Always assuming the screening cells and the pane are from the same manufacturer and being tested in the same method)
  3. In my case, temperature, as the screening cells and panel were both from the same manufacturer, therefore the same buffer system
  4. Because I've seen so many of them…………. But actually if your panel is not in the same buffer then pH or ionic strength could be the culprit rather than the temperature. Important to stress that these cold anti-Ms (in that they dont react strictly at 37°C) have no clinical significance. If it happens again, you can try the following: 1. Repeat the panel, incubating for 15mins at RT (on a Coombs card). The results will be stronger in this case. AND 2. Repeat the screen in the following way. Warm the cells to 37°C (best just to use a small aliquot - you dont want to 'cook' the whole bottle). And put the Coombs card (foil still on) in the incubator for 15mins. Put the patient's plasma in the incubator. IN the incubator, pipette 50ul of cells into the appropriate wells followed by the patient's plasma. Incubate for 15mins. At the same time, start the centrifuge empty. This warms the centrifuge up a bit. After 15mins put the incubated card into the centrifuge which will have now stopped and centrifuge immediately. This should negativise the screen results. This is about the nearest you can get to doing a gel test at strictly 37°C
  5. and what is wrong with this patient? what drugs is (s)he on?
  6. It depends a bit on how you work. If you are working manually then it is quite common to pipette a whole series of tests . In this time the cells can cool down enough for the anti-M to latch on, and once it's on it stays on. On the other hand, panels tend to go up individually so the cells stay warmer
  7. I'm no longer working but if this is an antibody then it sounds logical that it could cause non-sp results…..
  8. The DAT MIGHT have a considerable IgA component. Some anti-IgG (and hence also poly) will pick up IgA more than others regardless of method.
  9. might be worth checking to see if she actually has antibodies to IgA
  10. The reverse cells are normally pooled. So the lady's antibody is probably reacting with some of the cells in the pool and not others. Usually the Rh pheno is the same on all the cells in the pools so it probably is not due to the anti-c unless your provider does not ensure that they are all the same, or one of them is a c-variant. Could easily be an anti-M or Lea or Leb though
  11. Also, the polyclonal (human) reagents will give false pos results in samples with pos DATS. But anyway, finding sufficiently good human antibodies to manufacture reagents from is getting harder and harder. So definitely monoclonal
  12. Are you working in gel? If so, repeat in tube. Tube is more sensitive for weak reverse reactions
  13. This is well known and there are indeed other threads concerning this. Transfused cells may have different densities to the patient's own cells and therefore when you spin the tubes in the centrifuge you may find that the transfused cells and the patient's cells separate. Then, depending on where you sample from in the tube, you will either get only transfused cells, only patients cells or a mixture, giving a mixed field. Typically instruments will select cells from the bottom of the tube, whereas pipetting by hand, one normally samples from the top, giving a discrepancy between the two methods.
  14. what are the antibodies and what is the reason for needing the titration?
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