1.3 Principles of transfusion medicine Flashcards
Which antibodies can cross the placenta?
IgG
If you are blood type A what antigens and antibodies do you have?
Antigen A
Antibody Anti-B
If you are blood type AB what antigens and antibodies do you have?
Antigens A and B
No antibodies
If you are blood type O what antigens and antibodies do you have?
No Antigens
anti-A and Anti-B antibodies
What extra sugars do blood types A and B have?
A: n-acetyl galactosamine
B: Galactose
What blood type is the universal donor and why?
O because there are no antigens on the surface so no one will recognise them as foreign
What blood type is the universal recipient and why?
AB as there are no antibodies in the blood to react
What blood type are the universal donor and receiver of plasma?
Donor: AB
Recipient: O
What are the structural genes of Rh?
RhD (present or absent)
RhCE (C c, E e)
What are the symptoms of an acute heamolytic transfusion reaction?
Uritcaria Chest pain Hypotension Diffuse intravascular coagulation Haemoglobinuria Back pain Acute renal failure
What is the most common cause of acute heamolytic transfusion reaction
Clerical error resulting in the wrong ABO group being given
What causes delayed heamolytic transfusion reaction
Previously formed antibodies which were not detected on the pre transfusion testing enter the system. These cells are coated with IgG and removed
What are the typical symptoms of delayed heamolytic transfusion reaction
Unexplained anaemia with or without jaundice typically 7-10 days after transfusion
What happens if a patient who is Rh - is given Rh + blood?
The donor will develop antibodies against Rh. This will remain in the system but not cause harm as there is no antigen for them to bind to.If the patient is given a subsequent transfusion with Rh + there will be a reaction as the previously formed antibodies have an antigen to bind to
How does haemolytic disease of teh newborn occur?
Rh - mother has a Rh+ baby. The blood will cross teh placenta into the mothers cirulation. The mother will create antibodies againt the Rh (anti-D). In subsequent pregnancies the IgG can cross the placenta into the fetus and coat the fetal red cells leads to reticuloendotheilal destruction of teh RBCs. Can lead to anaemia, jaundice, hydrops, fetal death and hyperbilirubinaemia
How does haemolytic disease of the newborn occur?
Rh - mother has a Rh+ baby. The blood will cross the placenta into the mothers circulation. The mother will create antibodies against the Rh (anti-D). In subsequent pregnancies the IgG can cross the placenta into the foetus and coat the foetal red cells leads to reticuloendotheilal destruction of teh RBCs. Can lead to anaemia, jaundice, hydrops, foetal death and hyperbilirubinaemia
How does haemolytic disease of the newborn occur?
Rh - mother has a Rh+ baby. The blood will cross the placenta into the mothers circulation. The mother will create antibodies against the Rh (anti-D). In subsequent pregnancies the IgG can cross the placenta into the foetus and coat the foetal red cells leads to reticuloendotheilal destruction of the RBCs. Can lead to anaemia, jaundice, hydrops, foetal death and hyperbilirubinaemia
What can you do as prevention?
Give Rh - women anti-D IM at 28 and 34 weeks pregnancy. Anti-D will coat the +ve D cells preventing the mother from forming Anti-D memory B cells
If the mother delivers a Rh + baby you will also give a dose 72 hours post partum
How does haemolytic disease of the newborn occur?
Rh - mother has a Rh+ baby. The blood will cross the placenta into the mothers circulation. The mother will create antibodies against the Rh (anti-D). In subsequent pregnancies the IgG can cross the placenta into the foetus and coat the foetal red cells leads to reticuloendotheilal destruction of the RBCs. Can lead to anaemia, jaundice, hydrops, foetal death, kernicterus (CNS damage) and hyperbilirubinaemia
What can you do as prevention?
Give Rh - women anti-D IM at 28 and 34 weeks pregnancy. Anti-D will coat the +ve D cells preventing the mother from forming Anti-D memory B cells
If the mother delivers a Rh + baby you will also give a dose 72 hours post partum
If you do intervention such as amnio or the mother had bleeding in early pregnancy you would also give it then
What test can you do to check for immune mediated haemolysis?
Direct coombs test - will detect presence of antibody coasted red cells in circulation
How are red cells stored?
In citrate dextrose adenosine at 2-6 degrees for up to 42 days
How are platelets stored?
Room temperature for 5 days
How is FFP/cryoprecipitate stored?
Frozen at -20 for up to 12 months
When do you use platelets?
To prevent or stop bleeding in patients with severe thrombocytopaenia or platelet dysfunction
When do you use FFP?
To replace clotting factors (wont have all clotting factors)
What is present in cryoprecipitate?
Factor VIII, vWF, fibrinogen and factor XIII
What are examples of plasma derived products?
Albumin
IV immunoglobulin
Specific coagulation fatcors
Specific immunoglobulins
What test do you use for antibody screening?
Direct coombs test
Patient serum is incubated with a panel of red cells expressing a wide variety of common antigens and anti-IgG
If antibodies are present there will be agglutination
What test do you use for antibody screening?
Direct coombs test
Patient serum is incubated with a panel of red cells expressing a wide variety of common antigens and anti-IgG
If antibodies are present there will be agglutination
What are the possible transfusion reactions?
Acute heamolytic transfusion reaction Anaphylaxis Anaphalyactoid reaction Sepsis Febrile non-hameolytic transfusion reaction Uritcaria Transfusion related acute lung injury Delayed haemolytic tranfusion reaction graft vs. host disease post transfusion purpura
