Transfusion Flashcards
Blood supply chain
Blood supply chain - Blood centre - Hospital blood bank
- Patient
Blood safety only check a few
Multiple regulatory bodies;
Blood Safety Quality Regulations 2005 (BSQR)
BSH guidelines
NICE guidelines
Guidelines for the Blood Transfusion Services in the UK (‘Red Book’)
UK Transfusion Laboratory Collaborative
Safety of blood, tissues and organs (SaBTO)
Serious Hazards of Transfusion (SHOT)
Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee (JPAC)
Health and Care Professions Council (HCPC)
General medical council (GMC)
UKAS ISO15189 – (previously CPA)
Medicines and Healthcare products Regulatory Agency (MHRA)
TRANSFUSION IS A HIGHLY REGULATED PROCESS !
TRANSFUSION IS A HIGHLY REGULATED PROCESS !
Blood tracking
- Allows for electronic tracking and ‘vein to vein audits’ of blood components
- All temperatures recorded via temperature monitoring systems such as ‘Connected Automated Monitoring +’ (previously known as Tutela)
- Reduces human interaction = reduces human error
- Records kept for 30 years
Blood donation
- Extensive rules & regulations
- In the UK, all blood components are sourced from donations made by voluntary unpaid donors.
- Restrictions on donors – dates of previous donations/ transfusions, pregnancy, CVD..
NOTE: PREVIOUSLY ANYONE LIVING IN THE UK 1980-1996 COULD NOT DONATE & ANYONE BORN AFTER 01/01/96 RECEIVED NON-UK PLASMA PRODUCTS
1) Donor selection
Two purposes:
- Protect the donor from harm
- Protect recipient from any ill effects of transfusion (infectious diseases)
First procedure
For ease not full examination look at medical history and do a finger prick test unless too long for each donor
Complete screening questionnaire - Highly personal questions
Donors must be?
- fit and healthy
- weigh between 50kg and 158kg
- aged between 17 and 66 (or 70 if you have given blood before)
- over 70s that have given a full blood donation in the last two years
Clinical donor restrictions
- minimum pre-donation Hb concentration is 125g/L for female donors and 135g/L
for males
- Donors asked to donate ~470ml of whole blood
- Should be no more than 13% of their total circulating volume
-normal interval between whole blood donations is 16 weeks
What are angiotensin converting enzyme inhibitors
Angiotensin-converting enzyme (ACE) inhibitors aremedications that help relax the veins and arteries to lower blood pressure. ACE inhibitors prevent an enzyme in the body from producing angiotensin II, a substance that narrows blood vessels.
What are the 4 DNA viruses that are capable of causing the development of human cancers
Epstein-Barr virus, human papilloma virus, hepatitis B virus, and human herpes virus-8are the four DNA viruses that are capable of causing the development of human cancers
What happens if a patient has had a transfusion
IF A PATIENT HAS HAD A TRANSFUSION THEY ARE EXCLUDED FROM BLOOD DONATION FOR LIFE!!!! THIS MUST BE DISCUSSED WITH THEM DURING THE CONSENT PROCEDURE !!!!
What is variant Creutzfeldt–Jakob Disease
Caused by same agent as Bovine Spongioform Encephalopathy (BSE) in cattle or ‘mad cow disease’. Disease causing agent is a PRION
Happens when humans eat infected meat
Can be transmitted from person to person via medical products/instruments/tissue grafts/human-derived growth hormones
What is Leucodepletion
Introduced in 1999 as a way of removing (99.9% of) white cells from all blood products (white blood cells are infectious in vCJD individuals)
Based on the theory that many TTI -causing pathogens are resident in the white cells, which can mount a significant immune response
NHS Blood & Transplant (NHSBT) stuff they provide for transplants
Blood components;
- RBCs
- Platelets
- FFP (Fresh frozen plasma)
- Cryoprecipitate
- Granulocytes
Stem cell transplants
Solid organ tissues (live & deceased donors)
- Note: National Organ Retrieval Service
- 5136 patients awaiting transplant in UK (Dec 2020, NHSBT)
- 2185 patients have received a transplant April – Dec 2020 (Dec 2020, NHSBT)
Tissue bank (particularly eye services)
Why are stem cells hard to use
They are not for everybody so finding a right fit can be tricky
What is the NHSBT
The NHSBT is where all the action happens in that this is where all the blood is tested for its specific blood group, tested for TTIs and separated into its specific components where necessary
Whole blood processing
1) Whole blood is mixed and hung up to filter
2) Filtration removes white cells & platelets from a donation
3) Centrifugation
4) Separation into RBC, Plasma, platelets, FFP, Cryo
How many blood donations a week
Approx 700 whole blood donations per week
What are the products of plasma
Plasma products:
Fresh Frozen Plasma (FFP)
Cryoprecipitate (Cryo)
Why is Plasma products
Cryoprecipitate (Cryo) used
- Clotting proteins
- Severe bleeding
When is FFP used
- Albumin
- Clotting proteins
- Bleeding
Red cells
Store: 2-6ºC
Shelf life: ~35 days
Donation number = Enables traceability
Blood Group & expiry:
Clear & unambiguous
States Blood Group & Rh status
Do not use after 23.59 of expiry date
RC antigen info:
Phenotype of donor RCs
Important for selection of units for those with Rh Abs
CMV-, HbS-, HEV-
Other important Antigen-neg info may also be listed (e.g. if ordering antigen negative units like M-)
Platelets
Store: 20-24ºC, agitated
Shelf life: 5-7 days
Indicated for the treatment or prevention of bleeding in patients with thrombocytopenia or platelet dysfunction
Usually only available in groups O, A or B, with only a small number of group AB platelets produced.
Fresh Frozen Plasma (FFP)
Store: <-25ºC
Shelf life:
Frozen: 36 months
Thawed: 4ºC – 24hrs
RT: 4hrs
Male donors only to reduce risk of TRALI
Should not be used for volume replacement for patients who are not bleeding
Source of Clotting factors, electrolytes, Protein C, albumin
Used to manage the coagulopathy of bleeding
What is RT
RT measures the conversion of fibrinogen to fibrin when added to plasma
Cryoprecipitate
Store: <-25ºC
Shelf life:
Frozen: 36 months
Thawed : RT: 4 hrs
DO NOT FRIDGE
- Rich in FVIII, vWF, Fibrinogen, FXIII & Fibronectin
- Should not be used for volume replacement for patients who are not bleeding
- Used to manage the coagulopathy of bleeding
NHSBT - Hospital
Process
Product validation - Check all mandatory testing complete
- Products labelled & stored - Orders sent in from the hospital via OBOS - Hospital Services issue products to hospital - Blood delivery to Transfusion lab
Controlled storage & transport
Correct conditions (temperatures) to ensure cells remain viable, safe and clinically effective
Red cells must be stored at 4 - 6°C. Higher temperatures will result in loss of viability
Supply and demand…
- ‘Red Cell Demand Forecast’ is used to calculate and set blood collection targets – this forms the basis for collection session planning
- Only 4 - 6 % of adult population can donate blood
People are:
- Too busy
- Inconvenient venue/opening times
- Loss of “community spirit”
Monitoring blood stocks
Blood Stocks Management Scheme (BSMS) Est 2001
- Aims to calculate how much blood is in the supply chain at any one time
Improves blood inventory management across the blood supply chain
Collects data about stock and wastage from hospitals and blood services in the UK and Northern Ireland
BUT… is reliant on regular entry of stock data from hospital participants to the BSMS – Entry is not mandatory!
Reported via VANESA central management system
Roles of a Transfusion Scientist
- Donation/ Collection
- TTI screening
- Component processing
- Patient testing
- Compatibility testing
- Product issue
Why are antibodies created?
Antibodies are created in response to ‘foreign’ antigens & help the
immune system distinguish ‘self’ from ‘non-self’
What do scientists us antigen antibody interactions for?
Transfusion scientists use these antibody/antigen interactions in the lab to:
- Classify blood based on the presence or absence of inherited antigenic
substances (or antigens) on the surface of redcells
- Determine blood type of patients
- Find safe & compatible donor blood for patients
RBC antigens
- > 36 blood group systems, >300 antigens
- Only 9 systems considered ‘Major’
RC antigens may be:
- Carbohydrate attached to lipid
- Carbohydrate attached to protein
- Protein
Ability to stimulate severe immune response resulting in RC agglutination & destruction
ABO inheritance
Inherit 2 alleles from a possible 3
The A & B alleles are DOMINANT
The O allele is recessive
ABO system
Anti-A & Anti-B antibodies:
- IgM
- Naturally occurring (≥4 months)
- Capable of causing intravascular
haemolysis
Group O:
No naturally occurring antibodies
Considered universal donor
RhD antigen
- Rh gene locus on the short arm of chromosome 1
- Rh System comprises approx. 50 antigens – largest blood group system
-Landsteiner and Weiner (1940) experimented with RCs from Rhesus monkeys & injected them into rabbits producing an antibody that when tested against human RCs, reacted with ~85% of the population.
RhD antigen
RhD antibodies are IgG class
- 417 amino acid polypeptide
ABO testing
- Patients blood is separated into red cells and plasma by centrifugation
- Red cells (expressing antigen) are mixed with a commercial serum containing known antibody
- Agglutination if antigen is present
This is process is known as FORWARD (Full) GROUPING
2) ABO testing
- To confirm the forward grouping result, we test the patient’s plasma for naturally occurring antibodies, i.e. Anti-A or Anti-B
- Vital the forward and reverse groups complement each other
- May discover ABO variants at this stage e.g. A2
This is process is known as REVERSE (Rapid) GROUPING
Patient plasma + Commercial RCs = Agglutination if antibody is present
Column agglutination
- Ready assembled test system
- During centrifugation RBC agglutinations are trapped on the top of, or through the gel column, indicating a positive result.
- Any non-agglutinated RBCs will descend to the bottom of the column, indicating a negative result.
Sample arrival
Sample receipt in lab
1) Sample integrity & labelling checks
2) Checking patient history
3) Booking in requested tests
4) Sample preparation & analyser loading
First test performed = Blood grouping - forward & reverse grouping
If antibody screen is negative, group specific units issued
What if?
We give the wrong blood group? It depends…
- RhD neg units to RhD pos patients = OK 🙂 - RhD pos units to RhD neg patients = anti-RhD antibody stimulation 🙁 - Group O can be given to A,B, or AB - Group A can be given to AB - Group B can be given to AB - Group AB can only be given to AB
2) What if The blood is out of the fridge too long?
The blood is out of the fridge too long?
- RCs can start to break down
- Components can leak out of RCs & into blood bag
- ↑K+ , ↑LDH, ↑Bilirubin, ↑Ca2+ into patient plasma if txd
What if We transfuse expired blood? It depends…
We transfuse expired blood? It depends…
- If it’s within 24 hours, probably nothing BUT…
- Not insured & not guaranteed not to cause a reaction
- Guidance STRICTLY prohibits it!
Platelets - We transfuse expired platelets?
We transfuse expired platelets?
- If it’s within 24 hours, probably nothing BUT…
- Not insured & not guaranteed not to cause a reaction
- Guidance STRICTLY prohibits it!
The platelets are stored incorrectly?
The platelets are stored incorrectly?
- If refrigerated, platelets are rapidly removed from the circulation
- Heat-altered platelets change shape & lose ability to aggregate
- If not agitated, platelets can aggregate & become activated, developing micro-thrombi which can result in patient thrombosis
Platelets antigens on its surface
Platelets have ABO antigens on their surface & may have reduced survival if transfused to an ABO-incompatible recipient (not usually clinically significant)
The FFP/ Cryo has been defrosted or stored incorrectly?
The FFP/ Cryo has been defrosted or stored incorrectly?
- If defrosted at too high temp = destroy clotting proteins
- If defrosted to quickly = destroy clotting proteins
- If cryo stored in fridge after defrosting = protein clumping & micro-thrombi
We transfuse expired FFP/ Cryo?
We transfuse expired FFP/ Cryo?
- Not insured & not guaranteed not to cause a reaction
- Guidance STRICTLY prohibits it!
We give the wrong blood group? It depends…
( Plasma products
We give the wrong blood group? It depends…
- RhD status is less significant regarding plasma products
- Products are frozen & so any trace RCs destroyed
- Group O should ONLY be given to Group O patients
- Group AB can be given to A,B,AB & O
What is considered universal donors
- Group A RhD negative is considered universal donor group for PLATELETS
- Group AB is considered universal donor for FFP
- Group AB is considered universal for CRYO
Issue problems
- Short expiry time from donation
- 35 days for red cells
- 5-7 days for platelets
- washed products 24hrs
- Processing time and storage at NHSBT reduces usable time even further
- Products may be reserved for a specific patient repeatedly without being used, e.g. Irradiated antigen negative blood
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