2 Flashcards
(102 cards)
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.