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Sunday, November 6, 2016

🔃COMPATIBILITY IN BLOOD TRANSFUSIONS🔃: RBC Vs FFP Vs PLATELETS


COMPATIBILITY: RBC TRANSFUSION 


In red cell transfusion, there must be ABO and RhD compatibility between the donor’s red cells and the recipient’s plasma. 


All healthy normal adults of group A, group B and group O have ANTIBODIES IN THEIR PLASMA against the red cell types (antigens) that they have not inherited


Among the ABO blood groups: 


Group A individuals have antibody to group B


Group B individuals have antibody to group A


Group O individuals have antibody to group A and group B


Group AB individuals do not have antibody to group A or B. So,



1 Group O individuals can receive blood from group O donors only ( as the antibodies against A or B in their plasma will react with any A or B antigens which enter the circulation)


2 Group A individuals can receive blood from group A and O donors 


3 Group B individuals can receive blood from group B and O donors


4 Group AB individuals can receive blood from AB donors, and also from group A, B and O donors ( as their plasma don't have any antibodies against any antigens)


RhD RED CELL ANTIGENS AND ANTIBODIES


Individuals very rarely make antibodies against these antigens, unless they have been exposed to them (‘immunized’) by previous transfusion or during pregnancy and childbirth.


A single unit of RhD positive red cells transfused to an RhD negative person will usually provoke production of anti-RhD antibody. This can cause: in a subsequent pregnancy, rapid destruction of RhD positive red cells.


Haemolytic disease of the newborn (HDN):


An Rh D-negative mother may first encounter the D antigen while being pregnant with an Rh D-positive child, or by receiving a blood transfusion of Rh D-positive blood. Now the mother's immune response to the fetal D antigen is to form antibodies against it (anti-D.) The fetal red cells are haemolysed, causing severe anaemia. HDN due to ABO incompatibility is usually less severe than Rh incompatibility.




PLASMA TRANSFUSION: COMPATIBILITY 


In plasma transfusion, group AB plasma can be given to a patient of any ABO group because it contains neither anti-A nor anti-B antibody. 


1 Group AB plasma (no antibodies) can be given to any ABO group patients


2 Group A plasma (anti-B) can be given to group O and A patients 


3 Group B plasma (anti-A) can be given to group O and B patients 


4 Group O plasma (anti-A + anti-B) can be given to group O patients only


FFP does not need to be Rh-compatible  (However, the unit will still be labelled as Rh +ve or Rh −ve); anti-D prophylaxis is not necessary in Rh D-negative recipients of Rh D-positive FFP


PLATELET TRANSFUSION: COMPATIBILITY 


The Platelet Concentrates( PCs ) transfused must be ABO-identical, or at least ABO-compatible, in order to give a good yield. ( ( Ideally, ABO identical units should be used but, in an emergency, ABO non-identical units can be used, although the improvement seen in platelet count post-transfusion may be less.)


Group O PC can be used for patients with blood groups A, B, and AB ONLY IF,  they are resuspended in additive/preservative solutions, or if negative for high titre anti-A/A,B 


ABO-incompatible PCs have reduced efficacy and, preferably, should not be used 

 

Rh-negative patients, in particular women of childbearing age, should receive, if possible, RhD-negative PC 

 

In the case of a transfusion of a RhD-positive PC to a RhD-negative women of childbearing age, 250 UI (50 μg) of anti-D immunoglobulin should be administered, a dose able to cover the transfusion of five therapeutic doses of PC in 6 weeks 


ACUTE EMERGENCY : COMPATIBILITY 


During an acute emergency, the blood bank may send group O (and possibly RhD negative) blood, especially if there is any risk of errors in patient identification. This may be the safest way to avoid a serious mismatched transfusion, in such situations. 



Reference: The Clinical Use of Blood, Handbook, WHO,

 Recommendations for the transfusion of plasma and platelets Giancarlo Liumbruno, Francesco Bennardello, [...], and as Italian Society of Transfusion Medicine and Immunohaematology (SIMTI) Working Party