Lecture 8: Blood transfusions Flashcards
What are agglutinins?
Naturally occurring pentameric IgM antibodies
Link RBCs together
What shape are ABO antibodies
IgM pentameric Abs
What is the main consequence of a transfusion with incompatible blood?
Intravascular lysis
Can lead to - shock, HT, tachycardia, renal failure, loin pain, DIC and death
Describe the ABO blood grouping system
A: A Ag, anti-B Abs
B: B Ag, anti-A Abs
AB: A and B Ags, no Abs
O: no Ags, anti-A and anti-B Abs
What is forward grouping?
Test the Ag on RBC surface
What is reverse grouping?
Test Ab in plasma
Who can AB give blood to and receive blood from?
Give to AB
Receive from AB, A, B and O
Who can A give blood to and receive blood from?
Give to A and AB
Receive from A and O
Who can B give blood to and receive blood from?
Give to B and AB
Receive from B and O
Who can O give blood to and receive blood from?
Give to AB, A, B and O
Receive from O
What are the frequencies of each blood group?
O - 46%
A - 42%
B - 9%
AB - 3%
What does coagulation at the top of a blood grouping card mean?
Positive reaction
What are atypical Abs?
Arise due to sensitisation with foreign red cell Ags caused either by previous blood transfusion or pregnancy
Can cause transfusion reaction if the patient is transfused with incompatible blood in the future
What is the direct anti-globin test (Coombes)?
Tells you if the RBCs are coated with an Ab
Positive after a transfusion reaction and in HDN
What is the indirect anti-globin test (Coombes)?
Tells you in the patient is positive for Rhesus and other blood groups