Introduction to Blood Transfusion Flashcards
blood donors key steps in blood donor selection (3)
healthy volunteer donors
Hb =
135g/l men
125g/l women
weight 50kg
blood components (4)
red cells
FFP- fresh frozen plasma
platlets
cryoprecipitate
blood products (2)
anti D immunoglobulin
prothrombin complex concentration
ABO system (4)
ABO gene- chromosome 9
A gene- A antigen red cells
B gene- B antigen red cells
O- lack of A or B antigens
Landsteiner’s Law (3)
when patient lacks A or B antigen the corresponding antibody is produced in their plasma
naturally occurring antibodies cause haemolysis of red cells expressing the specific antigen
makes ABO antigen most clinically signifiant blood group system
ABO system- population (4)
O-47%
A-42%
B-8%
AB-3%
blood group compatibility (4)
Donor O- compat with O A B AB
Donor A- compat with A AB
Donor B- compat with B AB
Donor AB- compat with AB
RhD antigen (3)
veyr immunogenic
anti D antibody can cause transfusionreactiond and haemolytic disease of the foetus/ new born
avoid exposing RhD negative people to antigen D through transfusion
aims of pre-transfusion testing (3)
identity ABO and RhD groups of patient
identify presence of clinically significant red cell antibodies
allow selection of appropriate blood for transfusion
ABO grouping (2)
use reagents with known antibody specificity to identify antigens present on red cell= antisera
use red cells with known antigen specificity to identify antibodies present in plasma= reagent red cells
antibody antigen reaction (2)
antigen on red cells + antibody spec for antigen of interest=
agglutination of red cells
ABO + D grouping (6)
- test red cells with anti A, B + D antisera
-identify antigens in red cells
-IgM reagents- direct agglutination - test plasma against reagent red cells of group A + B
-identify antibodies in the plasma
DEFINE PATIENTS BLOOD GROUP
antibody screening (3)
- test plasma against several reagent red cells which express a known range of antigens
- identify antics in plasma
-use IAT- addition of AHG
indirect antiglobulin test (4)
- reagent red cells expressing known antigens
- add patient plasma
- add anti-human globulin (AHG)
4.look for agglutination- agglutination indicates presence of antibody
selection of blood for transfusion
matched for or compat with patents ABO + RhD group
consider presence of red cell anitbdodies
perform IAT crossmatch to check donor cells are compatible with patient plasma
main indications for red cell transfusions (4)
-symp anaemia - Hb < 70g
-major bleeding
-transfuse single unit of red cells then reassess patient
-consider cause before transfusion
main indications for platelet transfusions (4)
-prophylaxis in patients with bone marrow failure and very low platelet counts
-treatment of bleeding in thrombocytopenia patient
-prophylaxis prior to surgery/ procedure in thrombocytopenia patient
-consider cause before transfusion
main indications for plasma (FFP) transfusions (5)
-treatment of bleeding in patient with coagulopathy (PT ratio> 1.5)
-prophylaxis prior to surgery or procedure I patient with coagulopathy (PT ratio 1.5)
-management of massive haemorrhage
-transfuse early in trauma
-NOT in absence of bleeding/ planned procedure
multi step process= transfusion (10)
- decision to transfuse and consent to patient
- request
- sample taking
- sample and request report
- testing
- component selection
- component labelling
- component collection
- prescription/ authorisation
- administration, monitoring for reactions and documentation
monitoring patient during transfusion (3)
obs before blood is commenced
obs at 15 mins
obs within 60 mins of completion
