Blood transfusions

Question 1

what happens to blood after someone has donated

Answer 1

centrifuged = separated into parts

Question 2

how long are red cells stored for

at what temp

Answer 2

stored for 35 days at 4 degrees

Question 3

how long is FFP stored for

at what temp

Answer 3

stored for up to 3 years at -30 degrees

needs to be thawed before usage

Question 4

how long is platelets stored for

at what temp

Answer 4

stored for 7 days at room temp
bag is rocked (agitation)

think platelet life span is 7-10 days!

Question 5

most blood donation products come from one donor only, which products come from a pool of donor blood

Answer 5

anti-D 
prothrombin complex 
IVIg 
human albumin 
Ig

Question 6

which chromosome number determines ABO grouping

Answer 6

chromosome 9

Question 7

what are the 3 allele options in ABO grouping

get one from each parent

Answer 7

A antigen
B antigen
no antigen (O = absence of A or B antigen)

Question 8

which ABO alleles are co-dominant over the other

Answer 8

A and B are co-dominant over O

Question 9

what is landsteiners law for ABO groupings

example for A, O and AB blood groups

clinical significance of this

Answer 9

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

Question 10

if you give someone with blood group A blood that is O what will happen

Answer 10

nothing - is compatible

Question 11

if you give someone with blood group A blood that is AB what will happen

Answer 11

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

Question 12

% of population RhD +ve

Answer 12

85%

Question 13

what alleles do you need to be RhD -ve

Answer 13

dd (2 copies of recessive d)

Question 14

what do people with RhD -ve have that RhD +ve don’t

Answer 14

anti-D antibody (bc they DONT have the antigen)

Question 15

is RhD +ve or -ve the ‘universal’ donor

why

Answer 15

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

Question 16

how do you do ABO grouping (2 stages)

Answer 16

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

Question 17

in ABO testing if antigen is present on RBC and you give the antibody (anti-A etc), what will happen

Answer 17

agglutination (clumping)

Question 18

indirect antiglobulin test for someone with blood group A

Answer 18

test their plasma (should contain anti-B) against RBCs with B antigens on them

= should agglutinate (clump together)

Question 19

for indirect antiglobulin test in ABO testing, what chemical do you need to use to facilitate agglutination

Answer 19

anti-human globulin (AHG)

Question 20

indications for blood transfusion (2)

Answer 20

symptomatic anaemia Hb<70g/L

major bleeding

Question 21

indications for FFP (fresh frozen plasma) transfusion

Answer 21

MUST HAVE BLEEDING and coagulopathy (PT ratio >1.5)

Question 22

cause of acute hemolytic transfusion reaction (2)

Answer 22

ABO incompatilbility - wrong patient

bacterial contamination

Question 23

where does the haemolysis occur in acute transfusion reactions
is it IgM or IgG mediated

Answer 23

immediate reaction = intravascular

IgM

(bc iMMediate)

Question 24

<5mins of transfusion
fever
flush
feeling of impending doom

Answer 24

acute haemolytic transfusion reaction - ABO incompatibility or bacterial contamination

Question 25

management of acute haemolytic transfusion reaction (3)

Answer 25

STOP transfusion
ABCDE
blood cultures for sepsis (bacterial contamination)

Question 26

30 mins into transfusion 
elderly 
raised JVP
SOB 
pitting oedema

Answer 26

transfusion associated circulatory overload (TACO)

Question 27

management of transfusion associated circulatory overload (TACO) (2)

Answer 27

diuretics (furosemide)

transfuse slower

Question 28

current transfusion
fever
rash

Answer 28

febrile non haemolytic transfusion reaction (mild, acute)

Question 29

management of febrile non hemolytic transfusion reaction (2)

Answer 29

paracetamol for fever

transfuse slower

Question 30

PMH allergy
current transfusion
mild urticarial rash
SOB

Answer 30

allergic transfusion reaction

can also present as severe anaphylaxis

Question 31

FFP transfusion

SOB but normal JVP

Answer 31

transfusion associated lung injury

no fluid overload like TACO
anti-leukocyte reaction to FFP

Question 32

management of allergic transfusion reaction (4)

Answer 32

adrenaline
anti histamine (chlorampheniramine)
salbutamol (for SOB bronchoconstriction)
steroids

Question 33

complication of chronic transfusions eg thalassaemia

Answer 33

iron overload - need iron chelating drugs

Question 34

5-10 days after transfusion

jaundice

Answer 34

delayed haemolytic transfusion reaction

Question 35

where does the haemolysis occur in delayed transfusion reactions
is it IgM or IgG mediated

Answer 35

extravascular - bc has had time to move from circulation (immediate reaction = intravascular)

IgG mediated (bc iMMediate = IgM)

Question 36

what electrolyte abnormality can out of date blood cause

Answer 36

hyperkalaemia