Transfusion medicine

Question 1

Blood donations tested for?

Answer 1

• ABO group and RhD type

Infection

Question 2

Which infections are blood donations tested for?

Answer 2

• HIV 1+2 abs
• Hepatitis BsAg
• Hepatitis C ab
• Syphilis ab
• HTLV ab

Question 3

Processing of blood donations?

Answer 3

1. Leucocyte depletion
2. centrifuged:
   - red cells
   - platelets
   - Plasma
3. Platelets sampled for
   bacterial testing
4. Special processes (eg irradiation, washing, hyperconcentration)

Question 4

Plasma centrifuged to which components?

Answer 4

Fresh frozen plasma

Cryoprecipitate

Question 5

Red cells in blood donations

1. shelf life?
2. storage temp?
3. how much time once out of fridge

Answer 5

1. 35 day shelf life
2. at 4 degrees
3. transfuse < 4 h after removing from fridge

Question 6

2 methods of getting them platelet concentrates in blood donations?

Answer 6

I. Pool 4-6 donors blood
II. Apheresis
- single donor

Question 7

Platelet concentrates in blood donations

1. shelf time?
2. storage temp

Answer 7

1. max for 7 days

2. Storage: 22oC

Question 8

Fresh frozen component in blood donations

1. storage
2. shelf-time
3. special processing

Answer 8

1. Plasma frozen to -30oC
2. 2 yr storage
3. I.Viral inactivation
   -Methylene Blue
   II. Solvent detergent
   treatment (Octaplas)

Question 9

Fresh frozen component in blood donations use?

Answer 9

For clotting factor replacement if bleeding

Question 10

Cryoprecipitate

1. how is it formed?
2. use

Answer 10

1. Precipitate that forms
   when thawing FFP
2. Fibrinogen

Question 11

When to give blood transfusion in anaemia?

Answer 11

If below Hb < 7g/dL

Question 12

acute haemolytic transfusion reaction timing?

Answer 12

are defined as fever and other symptoms/ signs of haemolysis within 24 hours of transfusion

Question 13

acute haemolytic transfusion reaction types?

Answer 13

I. transfusion-related acute lung injury (TRALI),
II. transfusion-associated circulatory overload (TACO),
III. transfusion-associated dyspnoea (TAD)

Question 14

acute haemolytic transfusion reaction sx?

Answer 14

Fever, renal failure

Question 15

Donor PLASMA compatibility: (also same with Platelets, FFP, cryoprecipitate)

Answer 15

Different from RBC compatibility 
A receives from A or AB
B receives from B or AB
O receives from any
AB receives from AB

Question 16

Blood clotting pathway (haemostasis)

Answer 16

1. Collagen and tissue factor exposed
2. Von Willebrand Factor binds collagen
3. Platelets adhere to vWF-collagen
4. Platelets activate and aggregate
5. Tissue factor initiates rapid thrombin generation on activated platelets
6. Thrombin converts fibrinogen to fibrin and
   completes platelet activation
7. Stable fibrin-platelet clot is formed

Question 17

How TF (tissue factor) initiates rapid thrombin generation on activated platelets

Answer 17

by causing release of Proteases FVII, FX, FIX, FXI and Co-factors FVIII and FV

Question 18

3 regulations of haemostasis

Answer 18

1. vWF activity is regulated by ADAMTS 13
2. Thrombin is regulated by Antithrombin and Activated protein C
3. Fibrin cleaved by Plasmin into fibrin degradation products (D-dimer)

Question 19

2 types of clinical disorders of haemostasis?

Answer 19

• Primary haemostasis disorders

- Coagulation pathway disorders

Question 20

Primary haemostasis disorders cause?

Answer 20

• defects in
  Platelets,
  VWF,
  vessel wall

Question 21

Primary haemostasis disorders sx?

Answer 21

• mucocutaneous bleeding eg epistaxis, purpura

- immediate bleeding

Question 22

Coagulation pathway disorders causes?

Answer 22

• defects in:
• Coagulation factors
• fibrinogen

Question 23

Coagulation pathway disorders presentation

Answer 23

• deep tissue bleeding (joints)
• delayed bleeding (weak clot forms and breaks, followed by secondary bleeding)
  Both can cause GI/CNS bleeds

Question 24

Laboratory investigations of bleeding?

Answer 24

1. Platelet count + blood film
Indicates platelet number (not function)
2. Coagulation screen
I. PT time 
II. aPTT time

Question 25

PT time?

Answer 25

``` Prothrombin time (PT) Time to fibrin clot formation ```

Question 26

aPTT time?

Answer 26

Activated partial thromboplastin time (aPTT) | Time to fibrin clot formation

Question 27

PT time result interpretation?

Answer 27

Detects abnormal FVII, (extrinsic pathway) FX, FV, FII, Fibrinogen (common pathway)

Question 28

aPTT time result interpretation?

Answer 28

Detects abnormal FVIII, FIX, FXI (intrinsic factors) FX, FV, FII, Fibrinogen (common pathway)

Question 29

How long Group and Save takes?

Answer 29

- takes 40 mins

Question 30

Group and save procedure?

Answer 30

- perform Indirect Antiglobulin Test screening and store sample - request this if blood might be needed but not inevitable.

Question 31

how long Crossmatch takes

Answer 31

5-40 mins

Question 32

Cross-match involves?

Answer 32

- laboratory will assign units for specific patient - 5 minutes if recent group and save - 40 mins if antibodies/no previous G+S (IAT crossmatch)

Question 33

Acute haemolytic transfusion reactions (AHTR) diagnosis?

Answer 33

confirmed by one or more of the following: • a fall of Hb • rise in LDH • positive direct antiglobulin test (DAT) • positive crossmatch

Question 34

Delayed haemolytic transfusion reactions (DHTR) def?

Answer 34

are defined as fever and other symptoms/ signs of haemolysis more than 24 hours after transfusion

Question 35

Delayed haemolytic transfusion reactions (DHTR) confirmed by? ?

Answer 35

- a fall in Hb or failure of increment | - rise in bilirubin

Question 36

Transfusion-related acute lung injury (TRALI)

Answer 36

- SOB - hypoxia - bilateral pulmonary infiltrate within 6 hours of transfusion

Question 37

TRALI diagnosis?

Answer 37

any 4 of: - high HR - high BP - Pulmonary oedema - Fluid retention - respiratory distress

Question 38

Transfusion-associated dyspnoea (TAD)

Answer 38

- respiratory distress within 24 hours of | transfusion that does not meet the criteria for TRALI, TACO or allergic reaction.

Question 39

what blood component mostly affected during transfusion?

Answer 39

IRON • 1 unit red cells contains ~250mg iron • Maximum iron excretion ~3mg/day

Question 40

which organs are in danger of iron overload post transfusion?

Answer 40

``` heart liver pancreas joints pituitary ```

Question 41

Main cause of iron overload

Answer 41

Regular transfusion (several years) -iron overload

Question 42

Management of iron overload

Answer 42

• minimise transfusion • long term iron chelation (desferrioxamine [s/c] or deferasirox / deferiprone [oral] )

Question 43

Transfusion associated circulatory overload (TACO) sx?

Answer 43

raised pulse & BP at 15 mins post transfusion

Question 44

Transfusion associated circulatory overload (TACO) mx?

Answer 44

Slow down the infusion and give frusemide.

Question 45

Major haemorrhage def?

Answer 45

- 50% of total blood volume lost in less than 3 hours - Loss of more than one blood volume within 24 hours (around 70 mL/kg, >5 litres in a 70 kg adult)

Question 46

Major haemorrhage primary management?

Answer 46

tranexamic acid bollus for 10 min followed by 8 hours iv infusion