Blood transfusion Flashcards
What divides blood groups?
Red cell antigens are expressed on cell surfaces and can provoke antibodies
What does ABO gene encode?
Glycosyltransferase
What do A and B genes code for?
Transferase enzymes
What is the A antigen?
N-acetyl-galactosamine
What is the B antigen?
Galactose
Are A, B and O genes dominant or recessive?
A and B are codominant and O is recessive
What are A group antibodies against?
B
What are B group antibodies against?
A
What are O group antibodies against?
A and B
What are AB group antibodies against?
AB group has no antibodies against A or B
Which type is the universal donor?
O
Which type is the universal recipient?
AB
What does RhD encode?
Protein antigen which crosses membrane and forms pore for unidentified molecule
Is RhD gene immunogenic?
Yes
If you are an RhD positive and are exposed to these epitopes then you are very likely to develop antibodies
How might an RhD negative individual be exposed to RhD+ cells?
Transfusion
Pregnancy and foetus expresses these cells
What are the consequences of an RhD- individual being exposed to RhD+ cells?
Anti-D may be produced
Can cause transfusion reactions or haemolytic disease in the newborn
Why is there a diversion pouch for blood donations?
First bit of blood is syphoned off as this is where most of the bacteria would be
Why may red cell transfusion be used?
Sever acute anaemia
Improve quality of life in incorrectable anaemia
Prepare a patient for surgery or speed up recovery
To reverse damage from own cells e.g. sickle cell disease
At what temperature are red blood cells stored?
4*C
At what temperature are platelets stored at?
-22*C
What are the uses of platelets?
Massive haemorrhage
Bone marrow failure
Prophylaxis for surgery
Cardiopulmonary bypass
What is the most common cause of ABO reactions and how is this prevented?
Vials mislabelled
2 different samples brought in
What is the Coombs test (DAGT) used for?
Detecting antibodies on surface of red blood cells
Can mums develop antibodies against foetal foreign antigens?
Yes
Important for tolerating RhD+ babies (can inherit from dad)
What are some possible complications of haemolytic disease of the newborn?
May die in utero
Profound haemolysis
Placenta can no longer detoxify the blood
Very high bilirubin levels and brain damage
What is anti-D prophylaxis for pregnancy?
At about 28 weeks, RhD-negative mothers are given anti-D to mop up red cells from neonate before mother can develop antibodies
