Blood transfusion Flashcards
Requirements for being a blood donor
healthy
17-65 years old
not anaemic
weight >50kg
how is blood processed to be analysed
it is centrifuged to separate into component parts
what is blood tested for in microbiology
HIV HBV HCV HEV HTLV syphilis
how are red cells stored
4 degrees for 35 days
how is FFP stored
-30 degrees for 3 years
how are platelets stored
22 degrees for 7 days
what is FFP
fresh frozen plasma
contains clotting factors
list blood components from the lab
red cells
platelets
FFP
cryoprecipitate
what is cryoprecipitate
derivative of FFP with fibrinogen
list blood products from the lab
anti-D
prothrombin complex concentrate
what is prothrombin complex concentrate used for
warfarin overdose
list pharmacy blood products from the lab
IVIG
human albumin
specific Ig eg VZV
where do RBCs display antigens
on their cell surface
on which chromosome are the genes for ABO system found
9
what do the A and B genes code for and what is the purpose
transferases which modify the H substance precursor on RBC membranes
A + B are dominant over O
true or false
true
A is dominant over B
true or false
false
A+B are co-dominant
O is silent
true or false
true
what is the genotype of Group A
AA or AO
what is the genotype of Group B
BB or BO
what is the genotype of Group AB
AB
what is the genotype of Group O
OO
which antigens are present on RBC in Group A
A
which antigens are present on RBC in Group B
B
which antigens are present on RBC in Group AB
A + B
which antigens are present on RBC in Group O
none
how many ABO genes do you inherit from each parent
1 from each
what is Landsteiners law
when an individual lacks A or B antigen, the corresponding antibody is made in the plasma
Which antibody is present in the plasma in Group A
anti-B
Which antibody is present in the plasma in Group B
anti-A
Which antibody is present in the plasma in Group AB
none
Which antibody is present in the plasma in Group O
anti-A and anti-B
Group O blood can be given to only group O, true or false
false
it can be given to all blood group types
Group AB can receive all blood groups and only give to Group AB, true or false
true
Group AB has anti-A and anti-B, true or false
FALSE
Group AB has no antibodies
describe genetic inheritance in the RhD system
2 alleles - 1 from each parent
D is dominant (positive)
d is silent (negative)
what is the genotype of RhD+
DD or Dd
what is the genotype of RhD-
dd
RhD is very immunogenic, what does this mean
it doesn’t take a lot of RhD+ blood to cause a RhD- person to make antibodies
in terms of blood transfusion, what is the best RhD status to give to a RhD- person
RhD- blood to a RhD- person
what are antigens
proteins expressed on cell surface
what are antibodies
formed in response to antigens that are not expressed on your cells
what are the aims of pre transfusion testing
aim to identify ABO and RhD group
aim to identify clinically significant RBC antibodies
what are the 2 techniques for ABO testing
antisera
reagent red cells
what is antisera test
tests the patients own RBC with standard reagent of known specificity - antiA, B, D
what is reagent red cell test
testing the patients own plasma with reagent RBC of known specificity - either Group A or B
what is agglutination
when antibodies bind to antigens and cause clumping
what does antisera identify
presence of antigens on patients RBCs
what does reagents red cell test identify
presence of antibodies in the patients plasma
what is antibody screening
tests patients plasma with a range of reagent RBC of known antigens
what is the purpose of antibody screening
to identify antibodies in patients plasma that could react to donor blood
how is antibody screening done
indirect anti-globulin test IAT
what is done in an indirect anti-globulin test
patient plasma is added to reagent RBCs
then anti-human globulin is added
then you look for agglutination
what does it mean if there is agglutination in antibody screening/IAT
antibodies are present due to previous sensitisation to foreign antigens that the body does not have
what is crossmatch testing and how is it done
done with IAT to identify if donor blood is compatible with patient plasma
do you want to see agglutination in crossmatch testing
NO - this means donor cells are incompatible with patient plasma
what suggests compatibility in crossmatch testing
no agglutination
what are indications for red cell transfusion
symptomatic anaemia <70 (<80 with cardiac disease)
major bleeding
what are indications for platelet transfusion
bleeding in someone with thrombocytopaenia
prophylaxis in someone with bone marrow failure and thrombocytopaenia
prophylaxis prior to surgery in someone with thrombocytopaenia
what are indications for FFP transfusion
bleeding in someone with coagulopathy
prophylaxis prior to surgery in someone with coagulopathy
massive haemorrhage
when should you not use FFP
in the absence of bleeding or planned procedure
what is the single most important thing to do when carrying out blood transfusion
positive patient identification at all times!!!
when should the blood bottle be filled in
at the bedside immediately after obtaining blood
when should patient observations be carried out during transfusion
before transfusion
15 min into transfusion
hourly
within 60 min of completion
mild fever is a worrying sign in transfusion
true or false
false
need to keep close eye on patient and can give paracetamol
