Blood Groups Flashcards
Week 3
What is the Ag and Ab in:
Type A
Surface Antigen A only
Anti-B only
What is the Ag and Ab in:
Type B
Surface Antigen B only
Anti-A only
What is the Ag and Ab in:
Type AB
A and B antigens
Neither anti-A or B
What is the Ag and Ab in:
Type O
Neither A or B antigens
Anti-A and anti-B
Describe the RhD system
Presence (+) or absence (-) of Rhesus D Ag
differences between ABO and RhD
Antibody presence
- ABO antibodies present at birth
- RhD is not and has to be sensitised
Strength of mismatch
- ABO mismatch causes STRONGER and more immediate reaction
How would someone develop anti-D antibodies
If they are exposed to the opposite Rh blood group
e.g Rh - person exposed to Rh + blood
What is the universal donor type for RBCs and why?
Type O (as no Ag host = no Ab to react)
What is the universal recipient for RBCs and why?
Universal Recipient = Type AB (no donor Ab in serum to react with hose Ag)
What blood type is given to trauma patients?
Type O-
can be given to any ABO/RhD
What are blood donations tested for?
- ABO and RhD groups
- RBC AB screening
- syphilis serology
- viral screening (HIV, HBV, HCV, HTLV)
Why are all platelet donations screened for bacterial contamination?
stored at room temperature so there is risk of bacterial growth
What are the two methods for pre-transfusion testing?
Type and screen
cross match
How is Type and Screen pre-transfusion completed?
Donor sample mixed with antibodies
Check patients history and details
How is Cross-match pre-transfusion testing completed?
Mix the patient’s serum w donor RBCs
Lack of agglutination = compatibility
Who should receive RhD- blood?
O- patients w anti-D,
O- females of childbearing potential,
females of child bearing potential w unknown blood group,
O- children.
Contents of RBC cause transfusion reactions. What do
K
Hb and bilirubin
IC complexes
cause?
K –> Arrhythmias
Increased Hb and bilirubin –> renal failure
Unconjugated hyperbilirubinemia –> jaundice
IC complexes –> vessel occlusions
What are the steps of transfusion reactions?
Agglutination (clumping)
Haemolysis (phagocytosis or lysis via complete proteins)
RBC contents released
What are the causes of acute haemolytic reaction?
ABO incompatibility or a transfusion-related acute injury from WBC contamination
Group A RBC infused into Group O host = most severe rea
What mismatch causes most severe reaction in acute haemolytic reaction?
Group A RBC infused into Group O host
What causes Delayed Haemolytic reaction?
host developing Ab against introduced Ag or iron overload
what are the symptoms of Haemolytic transfusion reactions?
- chills and fever
- urticaria
- flank and back pain
- hematuria
- dizziness
- acute or delayed
What is done to manage suspected transfusion reaction?
Antihistamines (allergic reaction)
Blood warmers
Maintain airways
What is the underlying mechanism of HDN?
Rh incompatibility
- Rh - mother, Rh + foetus
mother’s immune system produces anti-Rhd IgG (sensitisation) in 1st preg
in subsequent preg, mother’s anti-Rhd IgG will cross placenta and attack Rh+ Foetus
