Blood transfusions Flashcards
what happens to blood after someone has donated
centrifuged = separated into parts
how long are red cells stored for
at what temp
stored for 35 days at 4 degrees
how long is FFP stored for
at what temp
stored for up to 3 years at -30 degrees
needs to be thawed before usage
how long is platelets stored for
at what temp
stored for 7 days at room temp
bag is rocked (agitation)
think platelet life span is 7-10 days!
most blood donation products come from one donor only, which products come from a pool of donor blood
anti-D prothrombin complex IVIg human albumin Ig
which chromosome number determines ABO grouping
chromosome 9
what are the 3 allele options in ABO grouping
get one from each parent
A antigen
B antigen
no antigen (O = absence of A or B antigen)
which ABO alleles are co-dominant over the other
A and B are co-dominant over O
what is landsteiners law for ABO groupings
example for A, O and AB blood groups
clinical significance of this
if someone lacks an antigen (A or B or both) they will make the corresponding antibody in their own plasma
eg someone with blood type A (AA or AO) will have anti-B antibodies
eg someone with blood type O (OO) will have anti-A and anti-B antibodies
eg someone with blood type AB will have neither anti-A or anti-B antibodies
if you give someone blood with an antigen in it and they have the anti bodies = haemolysis
if you give someone with blood group A blood that is O what will happen
nothing - is compatible
if you give someone with blood group A blood that is AB what will happen
haemolysis
bc blood type A = has developed antibodies against B (anti-B)
if you give AB blood = anti-B will react against B antigens = haemolysis
% of population RhD +ve
85%
what alleles do you need to be RhD -ve
dd (2 copies of recessive d)
what do people with RhD -ve have that RhD +ve don’t
anti-D antibody (bc they DONT have the antigen)
is RhD +ve or -ve the ‘universal’ donor
why
RhD -ve
bc -ve has the anti-D antibody bc they lack the antigen
so if you give someone who is RhD +ve some RhD -ve blood they will be fine
but if you give someone who is RhD -ve some RhD +ve blood, they have anti-D antibodies = haemolysis against D antigens in donor blood
how do you do ABO grouping (2 stages)
use anti-A, anti-B and anti-D reagents (antisera) to see which antigens are present on the RBCs
indirect antiglobulin test - essentially same but back to front, test patients plasma (will contain/not anti-A/B/D etc) on RBCs with known antigens
in ABO testing if antigen is present on RBC and you give the antibody (anti-A etc), what will happen
agglutination (clumping)
indirect antiglobulin test for someone with blood group A
test their plasma (should contain anti-B) against RBCs with B antigens on them
= should agglutinate (clump together)
for indirect antiglobulin test in ABO testing, what chemical do you need to use to facilitate agglutination
anti-human globulin (AHG)
indications for blood transfusion (2)
symptomatic anaemia Hb<70g/L
major bleeding
indications for FFP (fresh frozen plasma) transfusion
MUST HAVE BLEEDING and coagulopathy (PT ratio >1.5)
cause of acute hemolytic transfusion reaction (2)
ABO incompatilbility - wrong patient
bacterial contamination
where does the haemolysis occur in acute transfusion reactions
is it IgM or IgG mediated
immediate reaction = intravascular
IgM
(bc iMMediate)
<5mins of transfusion
fever
flush
feeling of impending doom
acute haemolytic transfusion reaction - ABO incompatibility or bacterial contamination
