T8 - Blood Collection and Processing

Question 1

Two Types of Blood Donation

Answer 1

Whole blood
- all blood components are collected
- separated to produce individual components (RBCs, plasma, platelets)
Apheresis
- blood is collected into an apheresis machine
- blood is separated
- plasma/platelets are collected
- RBCs returned to donor

Question 2

Whole Blood Collection

Answer 2

Blood is collected via the antecubital vein
Into a plastic collection bag, which contains anticoagulant
Each bag has a unique barcode so it can be traced

Question 3

Processing Whole Blood

Answer 3

Blood centrifuged
- separates whole blood into RBCs, plasma and buffy coat
Separated whole blood unit is placed on the Macopress blood separator
- separates blood components into different bags
- plasma and RBCs => new bags
- buffy coat (containing platelets) remain in original bag

Question 4

Processing Whole Blood - RBCs

Answer 4

Leukoreduced to minimise the number of white cells present
Decreases incidence of certain adverse transfusion reactions
Additive solution is added:
- SAGM
- saline
- adenine and glucose - maintain viability
- mannitol - prevents haemolysis

Question 5

Processing Whole Blood - Platelets

Answer 5

Buffy coat from four donors of the same ABO and Rh(D) group are combined
Individual bags, containing the buffy coat, are joined together and hung with a bag of platelet additive solution (PAS)
Bags are washed with PAS and washings are collected in the last bag
Bag is centrifuged and put on the Macopress, where the platelets are separated from the RBCs

Question 6

Apheresis

Answer 6

Separation of cellular elements from plasma
Used in Australia to collect plasma or platelets from donors
Apheresis donations can be performed on a more regular basis
- plasma - every two weeks
- platelets - every two or four weeks
- whole blood - every twelve weeks

Question 7

Apheresis Procedure

Answer 7

Blood is drawn from the donor into a centrifuge
Centrifuge separates the blood
Plasma/platelets are collected
RBCs +/- white cells and platelets are returned to the donor
Components are collected into:
- plasma - sodium citrate
- platelets - acid citrate dextrose
Components don’t require further processing

Question 8

How can apheresis be used therapeutically?

Answer 8

Plasma exchange
- thrombotic thrombocytopenic purpura
- post-transfusion purpura
- treatment of immune conditions
RBC exchange
- sickle cell disease

Question 9

Indications for Blood Transfusion

Answer 9

Blood loss
Anaemia
- [Hb] < 70 g/L in healthy person
- [Hb] > 70, < 100 g/L in certain populations
- not for [Hb] > 100 g/L unless actively bleeding
- patient tolerance of anaemia
Replacement of cells
Replacement of specific plasma factors

Question 10

Indications for not Transfusing Blood

Answer 10

Undiagnosed or asymptomatic anaemia
Post-operative haemoglobin > 80 g/L
Reversible short-term anaemia
Anaemia responsive to therapy
Improve general “well being”

Question 11

Red Cells - When to Transfuse?

Answer 11

Indications
- replacement of traumatic or surgical blood loss
- clinically significant anaemia in the absence of other treatment options e.g. Fe, B12
One unit should increase adult [Hb] by ~10 g/L
Stored @ 2-6°C for maximum of 42 days
Must be transfused within 30 mins of removal from storage
Leukocyte depleted

Question 12

Platelets - When to Transfuse?

Answer 12

Either single donor (apheresis) or pooled (whole blood)
Indications
- bleeding due to decreased production or functional abnormality
- postoperative bleeding – plts < 50 x 10^9/L
- thrombocytopaenia secondary to other conditions – plts < 10 x 10^9/L
Not where thrombocytopaenia is due to platelet destruction (TTP, ITP, HIT)
Should be ABO and Rh(D) compatible with recipient
One unit ↑ plt count by 20-50 x 10^9/L
Stored for 5 days @ 20-24°C with gentle agitation
Should “swirl” before given to the recipient

Question 13

Fresh Frozen Plasma - When to Transfuse?

Answer 13

Collected from whole blood or by apheresis, then frozen
Contains all coagulation factors
Indications
- coagulopathies (where a specific tx isn’t available)
- bleeding patients who require factor replacement
- warfarin OD (PCC preferred)
Not for volume replacement
Preferably ABO identical to recipient, must be ABO compatible
XM not required before issue
Stored @ -25°C
Thawed and transfused within 5 days

Question 14

Cryoprecipitate

Answer 14

Cold-insoluble fraction of thawed plasma
Contains factor VIII, von Willebrand factor, fibrinogen, factor XIII, fibronectin
Indications
- decreased plasma [fibrinogen]
- dysfibrinogenaemia
- disseminated intravascular coagulation (DIC)
Not for tx of haemophilia, von Willebrand’s disease, factor XIII deficiency
Stored @ -25°C
One unit per 5-10 kg body weight will ↑ Fbg by 0.5-1.0 g/L
Preferably ABO identical/compatible

Question 15

Cryoprecipitate Depleted Plasma

Answer 15

Remaining supernatant from cryo production
Contains all factors BUT those in cryo
Indications
- plasma exchange in TTP
- coagulopathies
- warfarin reversal
Stored @ -25°C
Preferably ABO identical/compatible

Question 16

Coagulation Factor Concentrates

Answer 16

Biostate
- contains Factor VIII and von Willebrand Factor
- treatment for von Willebrand’s Disease
Prothrombinex-HT
- Prothrombin Complex Concentrate (PCC)
- contains factors II, IX, and X
- used for warfarin reversal
Monofix
- purified factor IX
- treatment of haemophilia B