Transfusions Flashcards
What determines blood type?
The red cell antigens present.
What are antigens?
Proteins displayed on cells that can trigger an immune response.
Which chromosome is the ABO gene found on?
Chromosome 9.
What blood type is seen if 1 ‘A’ gene and 1’O’ gene are combined?
‘A’, as this is dominant over ‘O’.
The same applies if ‘B’ rather than ‘A’ is present.
What antigens are expressed in type ‘O’ blood?
None
How many ‘O’ genes are required for ‘O’ type blood?
2
What is the result of an ‘A’ gene and a ‘B’ gene together?
‘AB’ blood.
What antibodies are produced to fight blood antigens?
Those to attack against blood antigens not observed in the phenotype.
Antibodies produced are IgM.
What antibodies exist in ‘A’ type blood?
Anti-B antibodies.
Converse also true for ‘B’ blood.
What antibodies exist in ‘AB’ type blood?
No antibodies present.
What antibodies exist in ‘O’ type blood?
Both anti-A and anti-B antibodies exist.
Which individuals can receive type ‘O’ blood?
Anyone, however ‘O’ group individuals can only receive ‘O’ blood.
Which individuals can receive type ‘AB’ blood?
Only ‘AB’ individuals, with these individuals capable of receiving any form of blood.
What blood groups can receive group ‘A’?
A
AB
The same applies for ‘B’
What blood can be given to group ‘A’?
O
A
The same applies for ‘B’.
What % of the population are RhD positive?
Around 85%.
What blood antibody can cause transfusion reactions and haemolytic disease of the newborn?
Anti-D antibody
This is highly immunogenic.
What are the aims of transfusion testing?
Identify ‘ABO’ and RhD grouping of the patient.
Identify any significant RBC antibodies present.
Allow selection of appropriate blood for transfusion.
How is ABO grouping determined?
2 steps -
Antisera
Reagent red cells
Will cause agglutination of cells.
What is IAT used to diagnose?
Presence of anti-D antibodies
When is red cell transfusion indicated?
Symptomatic anaemia with Hb < 70g/L
Major bleeding
Important to also treat the underlying cause.
When is platelet transfusion indicated?
Prophylactically in those with bone marrow failure or a very low platelet count
Treatment of bleeding in those with thrombocytopenia
Prophylactically in those with thrombocytopenia undergoing surgery
When is fresh frozen plasma (FFP) given?
Bleeding with a coagulopathy (PT >1.5)
Prophylactically prior to surgery in those with a coagulopathy
Massive haemorrhage
When should fresh frozen plasma (FFP) not be given?
In the absence of bleeding/a planned procedure - even in the presence of an abnormal coagulation screen.
When should observations be taken during a transfusion?
Prior to initiation
15 mins after initiation
60 mins following completion
