Transfusion Medicine Flashcards
• What are the age limits for blood donors?
17-70 (but no age limit for regular donors
• What are the major risks of transfusion
- Transfusion transmitted infections
- Immunological reactions
- Overloading
i. Of iron → haemochromatosis
ii. Of fluid → pulmonary oedema & death
• What are the classical features of haemolytic transfusion reaction?
- Fever & tachycardia
- Backache (due to kidney failure from haemolysis)
- Dark urine (due to haemolysis and haemoglobinuria
• What products are available for transfusion and know a bit about them
Red cells
- stored at what temp and for how long?
- used for who?
- Stored at 4°C for up to 35 days
- used for people who have lost blood and for people with chronic anaemias
• What products are available for transfusion and know a bit about them
Platelets
- stored at what temp and for how long?
- used for who?
- Stored at 22°C for up to 7 days
- Used in thrombocytopaenia
• What is apheresis donation?
you hook the donor up to a machine that uses a centrifuge so separate the blood into the components and then you take what you want and give the rest back
• What products are available for transfusion and know a bit about them
Fresh frozen plasma (FFP)
- stored at what temp and for how long?
- used for who?
- For the clotting factors
- Stored at -30°C for up to 2 years
• What products are available for transfusion and know a bit about them
Cryoprecipitate
- how do you obtain it?
- used for who?
- As you thaw FFP, a white fluffy layer forms on top, which is called the cryoprecipitate
- It is rich in fibrinogen – used for fibrinogen replacement
• Why don’t we give whole blood transfusion?
o Most people only need one component of blood (e.g. RBCs for anaemics)
o By not always transfusing plasma, you reduce the risk of transfusing harmful antibodies
• What is a major and minor incompatibility?
o Major incompatibility = recipient has antibodies against transfused blood (e.g. group A blood given to group O patient). This activates complement and causes haemolysis.
o Minor incompatibility = blood has antibodies against recipient cells (e.g. group O blood given to group A patient).
• How are your blood antigens and antibodies related?
O
A
B
AB
Antibodies formed?
As a result: Groups suitable for red cell transfusion in each?
Groups suitable for plasma transfusion
The ABO antigens are found on the red cells; the ABO antibodies are in the plasma
O anti-A & anti-B
A anti-B
B anti-A
AB none
O= Group O A = Group A or O B = Group B or O AB = Group AB, A, B or O
O = Group AB, A, B or O A = Group A or AB B = Group B or AB AB = Group AB
o What you want to avoid is giving any antibodies to someone that they don’t already have
the universal acceptor of plasma ?
universal donor of plasma ?
o Group O is the universal acceptor of plasma because those people have all the antibodies already so it doesn’t matter what antibodies you give them, they already have it
o Group AB is the universal donor of plasma because those people don’t have any antibodies. You can only give AB plasma because only that plasma has no antibodies.
What is the prevalence of the ABO blood groups in the UK?
o O = 44%
o A = 42%
o B = 10%
o AB = 4%
haemolytic disease of the newborn?
• How is this disease prevented?
Anti-D immunoglobulin is transfused into the mother at the time of delivery in order to mop up any RhD+ RBCs that may enter the mother. This prevents mum from making any antibodies.
- What is the difference between a group & save, and a crossmatch?
- How many group and save samples does a lab need before doing a cross match and issuing blood?
Group & save is requested when there is not an urgent need for blood, but you still want to know what blood type the patient is. (40 MINS )
This is when you physically mix donor cells and recipient serum to see if there is any reactivity in a test tube, ➢ Takes 5 mins if patient already has a group and save, otherwise takes 45 mins
2, which have to be done half an hour apart and on different blood draws. This is to reduce the risk of a patient getting the wrong blood because of a labelling error.
