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Clarest last won the day on July 9 2017

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About Clarest

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  • Birthday 10/21/1971

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  1. Clarest

    Extending specimens past 3 days

    Our PreAdmit patient samples are valid for 30 days after collection if patients have not been pregnant or transfused in the last 3 months. We usually perform the group and screen test on the day of collection and if applicable, antibody workup ASAP. If required, we usually do the crossmatch one the day before the scheduled surgery date. Previously, we had separated plasma from cells for all samples. After we did validation to show that the reactions strength of ABO antibodies in the unseparated samples on their 30th days is comparable to that in the separated plasma, we stopped separating plasma if the antibody screen is negative and only immediate-spin crossmatch is required.
  2. Clarest

    Elution Studies

    Below is the source of my 1st question. " If the patient has been transfused within the past three months, but not within the last three weeks, an elution may be omitted if all of the following apply: a). The DAT was positive on the last specimen tested (i.e. collected more than three weeks ago) and was investigated, and b). The positive DAT (i.e. strength of the reaction) on the current specimen is not stronger than the DAT performed on the last specimen, and c). The antibody screen (i.e. strength of the reaction) on the current specimen is the same as on the last specimen. Note: Clinical circumstances, evaluation of transfusion, test result history and/or specimen history may override the above criteria and elution may be desirable for selected patients." Could any one explain why "three weeks" is specified here but a longer or shorter duration? Thank you.
  3. Clarest

    Elution Studies

    Hi Malcolm, Look at what I found in the link below http://www.transfusion.ca/Resources/CSTM-Blog/January-2017/I-will-remember-you-Malcolm-Needs Clarest
  4. Clarest

    Elution Studies

    Hi Malcolm, 1. I agree with you if we suspect there is a transfusion reaction which causes the positive DAT with IgG, it makes sense to do an elution on the new sample in case some other antibody(ies) are being detected this time but not from the previous sample. 2. Even we test an eluate once every month for the patient with an autoantibody, it is exactly as what you said the eluate shows pan- agglutination. Unfortunately, we do not perform alloadsorption on site. So, the eluate really does not mean that much for detecting underlying alloantibody(ies) developed due to transfusion reaction, especially when the auto is strong and the eluate always shows 3 to 4+ reaction strengths. Do you think it's necessary to send to our Reference Laboratory once every month for an alloadsorption or just send out when there is a sign of hemolysis process going on? Clarest
  5. Clarest

    Elution Studies

    We do exactly the same as Laurie said. I would like to take this opportunity to do another survey related to elution studies. 1. After a patient was transfused a couple of days or a week ago, we received a sample and did elution on it due to positive DAT with IgG. Then, several days later (no transfusion after the last elution) , another sample was received and the DAT was still positive with IgG. Do you do another elution as the patient has been transfused in the last 3 months? 2. If a patient has an autoantibody ( DAT is always positive with IgG) and has been frequently transfused (please do not ask me why?), do you do the elution on every post-transfusion sample received (e.g., every 96 hours or weekly) before crossmatching for the next transfusion? If not, how often do you perform the elution if the positive DAT (i.e. strength of the reaction) on the current specimen is not stronger than the DAT performed on the last specimen, and the antibody screen/panel (i.e. strength of the reaction) on the current specimen is the same as on the last specimen? Thank you.
  6. As Malcolm mentioned " as the anti-B in those units tend to be of lower titre and avidity than does the anti-A in either group B or O units". The patient is group AB and the red blood cells have A and B antigens.
  7. Hi Mabel, We use the tube saline IAT method for crossmatch and it is allowed to skip the immediate-spin phase. So, as long as the anti-A1 does not react at 37C, we have no problem to result the compatibility of the crossmatch. Routinely, it is okay for us to give group O or B blood for patient's with anti-A1 and that's what technologists prefer to do as it only requires immediate spin. However, for this particular patient, we just wanted to be more careful. Clarest
  8. Hi tkakin, You're right that anti-A1 typically reacts at immediate spin and that's reason for us to give group A or AB IAT crossmatch compatible red cells. On the other hand, if the group A or AB units are IAT crossmatch compatible with patient's plasma, it proves the anti-A1 does not react at 37C. Clarest
  9. Hi Malcolm, We gave group A IAT crossmatch at first when group AB was not available in our stock. Then, we particularly ordered group AB units to hold for this patient. I am really interested in the paper you mentioned in your post regarding AB antibodies. When you have time, could you please share it with us? Thanks a lot. Clarest
  10. Thank you Malcolm. We do not usually keep group AB red cell units in our stock.
  11. Hi all, If a sickle cell disease patient is group A2B with anti-A1 (seems no reactivity at 37 degree), which ABO group of donor cells is the best choice for transfusion, group O or B immediate-spin crossmatch compatible, or group A IAT crossmatch compatible? Thank you for your reply. Clarest
  12. Thank you all for your replies. They're really helpful.
  13. Hi all, We have a patient with strong rouleaux and an alloantibody. According to our policy, we need to perform a full crossmatch which means the crossmatch is carried from immediate spin, to 37C and to AHG phases. Due to the strong rouleaux, a saline replacement technique has to be used during the immediate spin crossmatch phase. I am wondering if the 37C and AHG crossmatch tests can be continued on the tube that has been done with the saline replacement. Thank you, Clarest
  14. Hi all, In the chapter 22 of 17th and 18th editions of AABB Technical Manuals, it states that "Multiple IM (intramuscular) doses should be given at different sites or at different times within 72 hours". I am wondering how to define the "multiple", more than one or 5 doses. The reason I mention "5" here is that in my previous and current working places, they either says "No more than 5 doses of RhIG should be injected intramuscularly at one time" or "If more than 5 vials of RhIG are required, they should be spaced out over 72 hours." I tried to find the base of these statement from the product inserts or monograph, but not successful. Could anybody share some information on this? Thank you. Clarest

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