2 Flashcards
Who discovered main blood groups?
Karl Landsteiner
What are the main blood groups?
A, B & O
Name the 5 main antibodies (also known as agglutinins) :
IgG IgM IgA IgE IgD
Which two of the Ig antibodies are larger in size?
IgM and IgA
Certain antibodies naturally occur in the blood from what age?
6 months old
Which antibodies are usually involved in the ABO grouping system?
IgM
Which system carries D C c E e antigens?
Rh system
A group of …… genes are inherited from each parent.
Rh (C,D or E antigens)
Which antigen is responsible for most clinical issues associated with the Rh system?
D antigen
A person can be RhD+ (D antigen is present) or ………..
RhD- (D antigen is not present)
The D allele is dominant so the genotype will either be…..
DD or Dd
Rh antibodies rarely occur …………
naturally
Before giving blood transfusion to a patient, a ………….. must be carried out.
crossmatch
Explain what a blood transfusion is.
The infusion of blood product from a donor to a recipient.
The compatibility of the donor and recipient is paramount. The ………… on their …….. may differ, causing problems eg. transfusion reactions.
proteins, RBCs
Outline the 3 steps of cross-matching blood.
1) mix the donor and recipient blood
2) incubate the mixtures at various temperatures
3) check for agglutination within the samples
What are some characteristics of an ideal donor?
-Age 17-70
-Weight > 50kg
-Not pregnant/lactating
-No risk behaviour (piercings, tattoo, risky sex, homosexual sex, acupuncture) within last 12 months
-Hb > 134g/L men
Hb > 120 g/L women
-no live vaccinations within last 2 months
Immune antibodies are given by…
transfusion or trans-placental pass during pregnancy
Immune antibodies are usually ………… but can be ………..
IgG
IgM
Which antibodies are the only ones capable of trans-placental pass from mother to fetus?
IgG
Immune antibodies usually react at ………. temperatures.
Warm eg. 37 degrees Celsius
What is the most important immune antibody?
Rh antibody: anti-D
Explain the importance of RhD- in pregnancy.
If a women has the dd genotype, they are RhD-.
This means they do not carry the D antigen. The baby however carries paternal antigens, for example the D antigen, so may be RhD+.
The mother will be exposed to the D antigen in the baby’s red blood cells, and IgG anti-D will be produced, as the D antigen is a foreign antigen to the mother.
The anti-D can cross the placenta and haemolyse the baby’s RBCs.
The first baby is unaffected since it takes time for antibodies to be produced- the mother is said to be sensitised.
However if a second baby is also RhD+, antibodies will be produced by the mother immediately, and these can reach the baby via the placenta. They will destroy the baby’s RBCs resulting in haemolysis of foetus/newborn. This is Rhesus Disease.
This may lead to anaemia/jaundice.
How are RhD- women treated in pregnancy?
Anti-D antibody is given to all RhD- mothers to prevent sensitisation. This will prevent her from producing the antibodies herself.
What are the 7 main things transfused?
Packed Red Cells Platelets FFP Cryoprecipitate Factor concentrates Immunoglobulins Human Albumin Solution
What does it mean when a Red blood cell is packed?
Plasma depleted
How long does it take to transfuse packed red cells?
usually 2-3 hours
How are platelets harvested?
They are by cell separators or from individual units of blood.
Platelets have to be stored at ………. …………
room temperature
Over what period of time are platelets transfused?
30 mins
What platelet count is usually aimed for?
> 10 but aim for >20
FFP (fresh frozen plasma) is stored at < ………….
-30 degrees Celsius
What does FFP contain?
coagulation proteins and inhibitors.
Indications that a platelet transfusion is needed:
- thrombocytopenia
- disordered platelet function & actively bleeding
Indications that a FFP transfusion is needed:
- dilutional coagulopathy
- liver disease
- DIC
What is DIC?
Disseminated intravascular coagulation.
A condition where blood clots are excessively formed in the body’s blood vessels.
Cryoprecipitate is rich in …………..
fibrinogen (clotting factor 1)
What is an immunoglobulin transfusion used for?
Treating immunodeficiencies.
What is transfused as a physiological plasma expander and how does it work?
Human Albumin Solution (HAS).
It is used to increase the oncotic pressure in the recipients blood.
It can also reduce oedema.
Early risks of transfusion:
Allergic reactions Pyrogenic reactions (rise in temp) ABO incompatibility Bacterial contamination Coagulopathy Circulatory overload Post transfusion purpura Transfusion related acute lung injury (TRALI)