Jump to content
April 2024 Challenge

Abdulhameed Al-Attas

Members
 View Profile  See their activity

  • Posts

    135

  • Joined

  • Last visited

  • Days Won

    1

  • Country

    Saudi Arabia

 Content Type 

Posts posted by Abdulhameed Al-Attas

    Rule out low incidence antibodies.

    in Immunohematology Reference Laboratories

    Posted

    • Low-incidence antigens are not usually found on screen cell and antibody panels.

    • Antibodies are hard to test for, but it is usually not difficult to find compatible blood.

    Suspect this antibody if an AHG crossmatch is incompatible and other causes have been ruled out, such as a positive donor DAT or ABO incompatibility.

    Examples of low-incidence antigens include: Cw, V, Kpa, Jsa.

    When going through the process of Ruling Out, antibodies like anti-V, anti-Cw, anti-Lua, anti-Kpa, and anti-Jsa usually fall into the "unable to rule out" category.

    Transfusion Reaction-Issuing additonal units

    in Transfusion Services

    Posted · Edited by Abdulhameed Al-Attas

    Yes, as Terri has mentioned the Medical Director is the one who interpretes the Transfusion Reaction,so untill he/she interpretes NO further Transfusions.

    And we put a note for that to alert coleuges.

    The reaction could be from Anti- IgA that requires either IgA deficiency blood or washed RBC's OR  FNHTR that may require Leukoreduced or HLA match in case of Platelets. 

    Second ABO/Rh sample

    in Transfusion Services

    Posted · Edited by Abdulhameed Al-Attas

    The ABO/Rh confirmatory policy has been developed to prevent transfusion from a misidentified sample.

    Our guidelines states unless electronic patient identification systems are in place, a second sample should

    be requested for confirmation of the ABO/Rh group of the first time patient prior to transfusion, where this

    does NOT impede the delivery of urgent red cells or other components.

     

    The ABO/Rh confirmatory is a STAT test and should be handeled accordingly, it must be from a seperate collection phlebotomy and collected at a different time from the initial one.

     

    It should NOT be a retained sample from the initial collection and delivered as a second one after Bank Bank calls for a ABO/Rh confirmatory sample.

     

    Yes,post 4 months of age, we require a confirmatory sample, as MAGNUM stated.

    We must always remember that the most important test done in the Blood Bank is ABO grouping. 

    How would you handle this scenario?

    in Transfusion Services

    Posted · Edited by Abdulhameed Al-Attas

    I agree with both David and Anna for their respective suggestions of an enzyme pretreated panel in gel and extended phenotype on the pre-transfusion sample.

    You have done an elution on the patient's post-transfusion red cells, and the resulting

    eluate tested for antibody specificity.

    Note  that in this case, even though the antibody elutes from the patient's red cells, it is NOT an autoantibody as it actually eluted from the donor's red cells now in the patient's circulation.

    Irradiated pRBCs for a patient with HLA antibody.

    in Transfusion Services

    Posted

    Irradiated Blood Products

    All pediatric cancer patients will receive irradiated blood products in order to prevent

    transfusion related graft-versus-host disease.

    Filtered Blood Products

    All pediatric cancer and sickle cell patients will receive filtered blood products. Filtration

    is an effective way to eliminate the risk of CMV infection in patients with cancer, and

    prevents alloimmunization.

    CMV Negative Blood Products

    CMV negative blood products will be reserved for cancer patients who are documented

    to be CMV seronegative and are scheduled to undergo a bone marrow transplant. At the

    time of transplant, these patients are more immunocompromised, and the low level of

    CMV that may remain in a filtered product can still pose a risk.

    Platelet refractoriness will be defined as inadequate rise in platelet counts as measured

    within 1 hour of platelet transfusion.

    Approaches to platelet refractoriness:

    1. Make sure platelets are ABO compatible.

    2. Ask for fresh units.

    3. Test for HLA antibodies and platelet specific allo-antibodies.

    4. Consider IVIG (0.5 gm/kg) and Amicar in patients with significant bleeding.

     

    REMEMBER always THE ONLY WAY one can prevent graft-versus-host disease

    is through IRRADIATION.

    I hope this will help.

    Antibody Titer methodology

    in Transfusion Services

    Posted · Edited by Abdulhameed Al-Attas

    Titre: The reciprocal of the highest serum dilution that causes macroscopic agglutination when serial dilutions of an antibody are tested against selected red cells.


    Applications:


    Prenatal testing 


    Identification of HTLA


    Comlex Antibody Identification 


    Differentiation of pathological and harmless autoanti- I  and  Procurement of antisera Quality assurance of reagents.


     


    Limitations:


    Titrations are only semiquantitative estimates of antibody reactivity due to several variables that affect their performance. Three main variables are the technologist, the red cells, and the method.


    Ways to Minimize Variables:


    1. technologist: experienced with proven technique
    2. red cells: ideally when titres of samples are to be compared, use fresh red cells (antigens deteriorate on storage) from the same donor (same number of antigenic sites present). If this is not possible, use commercial red cells of the same apparent genotype.
    3. method: when sequential samples are examined for change in titre, store samples frozen and run new samples in parallel with the immediately preceding sample. This is the most practical way to control that an increase in titre is real.

    Prozone Phenomenon:


    This may cause reactions to be weaker in the first tubes than in higher dilutions and is believed to be caused by an antibody excess in which all antigenic sites are sensitized with antibody leaving none free to form cross-links


    Significant Difference in Titres:


    When comparative studies are done, such as in prenatal testing, a difference in titre of at least 2 tubes is required to be considered a significant difference. For example, if the titre changes from 32 to 64, this is not considered to be significant (difference of only 1 tube); however, a change from 32 to 128 would be significant (2 tube difference).


    These are the important points to know about AntibodyTitration.


    Albumin as Contol

    in Transfusion Services

    Posted · Edited by Abdulhameed Al-Attas

    As Anna, mentioned above ''You need to use a control that is equivalent to the reagents you are controlling''.

    that is to say, from the same manufacturer of your Anti-D. The Rh control contains everything that is present in the anti-D typing sera except the anti-D.

    If Rh control is not available then you can use from 6-8% Albumin Because the Albumin added to the Rh control is about 6-8%. And as David said above,The control is necessary (especially in apparently group AB positive patients).

    Another application is to use as a negative control when testing a Du or Weak D.

     

     

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.