Transfusion Medicine Flashcards
What determiens blood group?
the antigens present on the surface of red cells
How are the blood natigens inherited?
in a mendelian fashion - 1 allele form mom and 1 allele from dad, but you COEXPRESS both of them
What are the two most important blood group systems?
ABO and Rh
How do you makes the A, B and H antigens for the ABO system?
- you start with a protein precursor
- add FUCOSE for the H antigen
- then add N-acetylgalactosamine to the H antigen to make A antigen
- OR you add galactose to the H antigen to make B antigen
So what antigen does pretty much everyone have? what’s the rare exception?
pretty much everyone has H antigen (except for the Bombay phenotype - they don’t even have that)
What do the genes for the ABO groups encode for?
A and B encode for the enzyme that causes the attachment of the galactose or the Nacetylgalactosamine
The O gene doesn’t really have a gene product
FOr the ABO group antigens, do you have to be exposed to something you don’t have to make antibodies, or do you make them from birth?
you do NOT have to be exposed
What is the antigen in the Rh system and how is it inherited?
the D antigen - it’s mendelian autosomal dominant, so
DD and Dd is Rh positive and dd is Rh negative
Do you have to be exposed to D antigen to make antibodies, or do you make them from birth?
This one you have to be exposed to
Why is it better that we separate blood into its components for donation now?
- it’s better to just give the patient what she needs
2. it conserves blood supply
What are the five main components whole blood can be separated to?
red cells, granulocytes, platelets, fresh frozen plasma and cryoprecipitate
What patients get whole blood?
the people with the massive traumatic bleeds
Who gets red blood cells?
People who are anemia but have normal blood volume (this is the one ost commonly given)
What are leukoreduced red blood cells and when do we use them?
It’s red cells that have been treated so there’s virtually no WBCs ot platelets - we use them on patients who hae had repeated febril transfusion reactions and in people who will b egetting lots of transfusions
How long can we keep RBCs frozen for the rare blood groups?
10 years
Who receives the granulocytes?
Only patients with severe neutropenia and sepsis (with an infection that’s unresponsive to antibiotics) - so rarely because it’s hard to obtain