Tuesday, October 20, 2015

Cross Matching

Cross matching is conducted when there is a case for blood transfusion. The correct blood should be provided to the patient in order to avoid any transfuse reaction which may worsen the patient's health condition.




Procedure:

  • Blood Grouping (Both Forward and Reverse)
    *Tile method is used for rapid test during emergency*
  • Centrifuge the plain tube.
  • Take the requested unit of the relevant blood bag ( packed cell / whole blood )
    And cut 1 segment from each blood bag to release small amount of the blood to different labelled test tubes.
    Wash 3 times and make 5% suspension.
  • Fill up the recipient card, place the card together with the blood bag and put them back to the fridge if the blood is not going to be collected immediately.
  1. Add 100μl of patient's serum (from red-capped plain tube)  and 50μl of the Donor's red blood cells into a clean test tube.
  2. Centrifuge for 15 seconds.
  3. If no agglutination occurred, add 2 drops of LISS reagent and incubate at 37°C for 15 minutes.
  4. Centrifuge for 15 seconds.
  5. If no agglutination, wash 3 times  and add 2 drops of AHG reagent.
  6. Centrifuge for 15 seconds.
  7. View under microscope if agglutination is not observed visually.




Result interpretation: 
    • No agglutination, add ccc ( Coomb's control cell/ checkcells ) to test the reliability of AHG
      *Should be have agglutination after centrifuge if the AHG reagent is valid *
    • Agglutination indicating the donor's blood is not compatible with the patient's body. thus the blood must not be transfused.



3 Phases
  • RT (Room temperature) phase   -- to test when cold antibodies can function.  Eg. IgM ( Lewis....)
  • LISS phase -- warm antibodies can function.  Eg:  1gG ( ABO )
  • AHG phase




Important Notes:
For newborn baby (less than 4 months), mother's blood/serum should be used for cross matching. Because, babies don't have antibodies yet.

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