18 Questions
What is the primary function of blood group antigens on the red cell surface?
To help distinguish between compatible and incompatible blood types
What is the primary difference between naturally occurring antibodies and immune antibodies?
Naturally occurring antibodies are produced following exposure to environmental antigens
What is the purpose of the ABO blood group system?
To classify blood types into A, B, AB, and O groups
What is the inheritance pattern of the ABO blood group system?
Co-dominant, with A and B being equally expressed
What is the significance of the universal donor and recipient in transfusion medicine?
Group O is the universal donor, and Group AB is the universal recipient
What is the consequence of transfusing incompatible blood?
Red cell destruction (haemolysis) in vivo
What was the main reason why Nurse 1 didn't check the patient's identity band?
Nurse 1 was familiar with the patient and assumed they knew their identity
Why did Nurse 1 remove the patient's ID band?
Because it was making it difficult to remove one of the patient's intravenous cannulas
What was the error made by Nurse 2?
Nurse 2 requested the unit for their own patient in error
What is essential for transfusion safety?
Positive patient identification
What is the purpose of organizing a blood transfusion?
To ensure the correct blood component is transfused to the patient
What is the learning objective related to blood grouping?
To explain how blood grouping affects the choice of components for transfusion
What is the primary goal of administering Anti-D immunoglobulin to RhD negative women?
To prevent haemolytic disease of the foetus and newborn
What is the significance of the 'Two sample rule' in pre-transfusion sampling?
It doubles the safety of the transfusion process
What is the primary consequence of giving RhD positive red cells to an RhD negative recipient?
Haemolytic disease of the foetus and newborn
What is the purpose of the 'crossmatch' test in laboratory testing?
To confirm the compatibility of donor and recipient blood
What is the primary symptom of an acute haemolytic reaction?
Pain in the chest or loins
Why is it important to positively identify the patient before transfusing?
To confirm the patient's identity and prevent mismatch
Study Notes
Blood Group Antigens and Antibodies
- Blood group antigens are proteins or polysaccharides on the surface of red blood cells, determined by genes and capable of stimulating antibody production.
- Antibodies are immunoglobulins in plasma that react with a specific antigen, produced against antigens not present on a patient's own red cells.
- There are two types of antibodies: naturally occurring (formed following exposure to environmental antigens similar to blood group antigens) and immune antibodies (formed following contact with blood group antigens).
ABO Blood Group System
- The ABO blood group system consists of polysaccharide antigens O, A, and B.
- Naturally-occurring antibodies are anti-A and anti-B.
- ABO grouping is performed by mixing patient cells with specific antisera and patient plasma with known red cells.
- ABO inheritance is determined by the genes encoding enzymes capable of synthesizing A and B antigens.
- The ABO blood group frequencies vary, but Group O is the universal donor and Group AB is the universal recipient.
Clinical Significance
- Recipients with anti-A or anti-B must not be transfused with donor cells expressing the corresponding antigen.
- Positive patient identification is essential to transfusion safety.
Rh Blood Group System
- The Rh ("Rhesus") blood group system consists of transmembrane proteins, with >50 antigens, and 'D' being the most immunogenic.
- Antibodies are immune only and form following exposure to RhD positive red cells through transfusion, pregnancy, or transplantation.
- RhD inheritance is determined by one gene (D/d) from each parent, with one copy of D making an individual D positive.
- RhD blood group frequencies vary, but it is essential to avoid giving RhD positive red cells to RhD negative recipients, especially women of child-bearing potential.
Haemolytic Disease of the Foetus and Newborn
- Consequences of haemolytic disease include foetal anaemia and neonatal jaundice, which can cause brain damage.
- Prevention involves administering anti-D immunoglobulin to RhD negative women to 'mop up' any RhD positive red cells entering maternal circulation.
Blood Transfusion
- Blood components include whole blood, red cells, platelets, fresh frozen plasma, plasma cryoprecipitate, clotting factor concentrates, immunoglobulins, and albumin.
- Ten steps are involved in transfusion, including pre-transfusion sampling, laboratory testing, and giving a transfusion.
- Positive patient identification is crucial before transfusing, and the patient's blood group and the donor unit's blood group must be confirmed.
Acute Haemolytic Reaction
- Onset is within minutes, causing intravascular haemolysis and a massive inflammatory reaction.
- Symptoms and signs include restlessness, fever, pain, tachycardia, nausea, and abnormal bleeding.
- Consequences can be severe, including shock, clotting abnormalities, renal failure, and death.
Learn about the science of blood groups, blood group antibodies, and their clinical implications for transfusion and pregnancy. Understand the differences between naturally occurring and immune antibodies, and the features of ABO and Rh blood group systems.
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