Blood Transfusion

Question 1

What is the minimum criteria for haemoglobin in men and woman respectively to be eligible to donate blood?

Answer 1

Men: Hb 135g/L
Women: Hb 125g/L
Minimum weight 50kg

Question 2

During blood processing and testing, what pathology is screened for in microbiological testing?

Answer 2

HIV
Hep B
Hep C
Hep E
HTLV
Syphilis

Question 3

List some blood products that can be acquired from batches of blood via manufacturing

Answer 3

Human albumin
Immunoglobulin
Prothrombin complex concentrates
AntiD immunoglobulin

Question 4

List components of blood available from the transfusion lab

Answer 4

Red cells
FFP
Platelets
Cryoprecipitate

Question 5

What must be done to donor blood to separate it into components?

Answer 5

Anticoagulation

Question 6

Who should avoid donating blood?

Answer 6

Infective risk
Transmitting disease (malignancy)
Drug addicts
Recent foreign travel to endemic areas

Question 7

Describe the order/position of blood components in a bag once blood has been centrifuged

Answer 7

Red cells at bottom (most dense)
Platelets + white cells in middle
Plasma at top (least dense)

Question 8

Describe how blood groups are formed in the ABO system

Answer 8

A and B genes, one inherited from each parent, code for transferases which modify precursors called H substance on red cell membrane

Question 9

What is Landsteiners law?

Answer 9

When an individual lacks the A or B antigen the corresponding antibody is produced in their serum/plasma

Question 10

What is the shelf life of donated platelets?

Answer 10

7 days if bacterial monitoring system applied

Question 11

At what temperature and for how long must fresh frozen plasma be stored?

Answer 11

-30’C for up to 3 years

Question 12

What are the possible blood groups a person can be?

Answer 12

A
B
AB
O

Question 13

Describe the red cell membranes of ABO blood groups, and the associated antibodies produced

Answer 13

A: carry A-antigen (anti-B antibody)
B: carry B-antigen (ant-A antibody)
AB: carry A-antigen + B-antigen (no antibodies)
O: no A or B antigen (anti-A and anti-B antibody)

Question 14

Order the blood groups from highest to lowest population frequency

Answer 14

O, A, B, AB

Question 15

Which of the ABO blood groups is the universal donor? Why?

Answer 15

O is universal donor because blood carries no antigen and therefore other blood groups won’t form antibody against it

Question 16

Which of the ABO blood groups is the universal recipient? Why?

Answer 16

AB is universal recipient because it carries both antigens and therefore won’t form antibody against any of the other blood groups

Question 17

Naturally occuring ABO antibodies are what - Ig?

Answer 17

IgM

Small proportion are IgG

Question 18

The genes that determine our ABO group are located on which chromosome?

Answer 18

Chromosome 9

Question 19

Which alleles for ABO group are dominant?

Answer 19

A and B are co-dominant

O is recessive

Question 20

The genes that determine Rhesus-D status are located on which chromosome? How are they inherited?

Answer 20

Chromosome 1

Inherit D or d allele, one from each parent

Question 21

Inheritance of Rhesus-D follows what pattern? What percentage of the population are RhD+

Answer 21

Autosomal dominant (d allele is silent)
85%

Question 22

What are the risks of RhD antigen exposure? How are these prevented?

Answer 22

Transfusion reactions
Haemolytic disease of the fetus and newborn
Avoid exposing Rh- to D antigen through transfusion

Question 23

What are the possible ways to carry out ABO grouping?

Answer 23

ANTISERA (ABO group)
Use reagents with known antibody specificity to identify red cell antigens:
REAGENT RED CELLS (antibody)
Use red cells with known antigen specificity to identify antibodies in plasma

Question 24

How is blood group determined?

Answer 24

Agglutination

Giving antibody to individual of same blood type (e.g. anti-A to group A) will cause cells to stick together

Question 25

What test is used to identify antibodies in the plasma during cross-matching of the blood?

Answer 25

Indirect antiglobulin test

Addition of antihuman globulin to plasma/red cell suspension causing agglutination if antibodies are present

Question 26

List possible indications for red cell transfusion in anaemia

Answer 26

Symptomatic anaemia (Hb <70g/l)
Heart disease (Hb <80g/l)
Major bleeding

Question 27

List indications for platelet transfusion

Answer 27

Prophylaxis in bone marrow failure and low platelets
Treatment of bleeding in thrombocytopaenia
Prophylaxis prior to surgery in thrombocytopaenia

Question 28

List indications for fresh frozen plasma transfusion

Answer 28

Treatment of bleeding in coagulopathy
Prophylaxis prior to surgery in coagulopathy
Management of massive haemorrhage
Transfusion early in trauma

Question 29

What action must be taken in an acute haemolytic transfusion reaction?

Answer 29

Stop blood transfusion
Give IV fluids
Obtain blood sample: transfusion, FBC, film, coagulation screen, biochemistry, blood culture, haptoglobin)

Question 30

What does haptoglobin do?

Answer 30

Binds free haemoglobin

Question 31

List differentials of an acute transfusion reaction

Answer 31

Acute haemolytic transfusion reaction

Bacterial contamination of blood (usually platelets)

Question 32

List signs of a transfusion associated circulatory overload

Answer 32

Respiratory distress within 6 hours of transfusion
Hypertension
Raised JVP
Positive fluid balance

Question 33

Outline management for transfusion associated circulatory overload

Answer 33

Oxygen and supportive care
Diuretics (furosemide)
Slow further transfusion
Identify patients at risk

Question 34

What type of reaction is ABO incompatibility?

Answer 34

Type 2 hypersensitivity reaction