Blood Transfusion Flashcards
ABO system?
naturally occurring antibody system against any antigen that’s not present on your RBC (in this case A,B,O)
type of antibodies in ABO system?
IgM antibodies
can cause potentially fatal haemolysis
IgM shape?
5-antibody, star-like shape
blood group vs antigens and antibodies?
BG A - have A antigens and anti-B antibodies
BG B - have B antigens and anti-A antibodies
BG AB - have A AND B antigens but neither antibodies
BG O - have neither A nor B antigens but both anti-A and anti-B antibodies
what exactly are ABO antigens?
glycoproteins
A and B are formed by adding a sugar residue (galnac and gal) to a common H antigen
Group O has neither of these sugar residues
Group AB will have both residues
most important antigen in Rh system?
D
blood groups in Rh system?
RhD positive and RhD negative
D gene - which is recessive/dominant?
D codes for D antigen and is dominant
d codes for no D antigen (i.e. RhD negative) and is recessive
what kind of antibodies are anti-D antibodies?
IgG
two implications of anti-D antibodies?
delayed haemolytic transfusion reactions
haemolytic disease of the newborn
do other antigen groups exist?
yes, but the aforementioned groups (ABO and Rh) are the most clinically important
in some patients these other antigens can interfere with transfusions
compatibility tests?
ABO group tests - test the patient’s RBCs with know anti-A and anti-B reagents. There will be agglutination
RhD group tests
Second part involves cross-match. This means the patient’s serum is mixed with the chosen donor RBCs - shouldn’t react. If there is agglutination then it’s incompatible.
how can whole blood be split up and donated?
whole blood - RBCs, platelets and plasma
plasma can be split into - FFP, cryoprecipitate
what is FFP given for?
people with clotting factor deficiencies (prolonged APTT and PT)
what is plasma given for?
coag factors
