2. What is it?
Transfusion medicine is a multidisciplinary science concerned with the proper
use of blood or blood products in the treatment or prevention of disease.
Optimal transfusion therapy requires knowledge of blood types and
crossmatching procedures, donor selection, blood collection and
administration techniques, component therapy, transfusion reactions, and
red blood cell (RBC) substitutes.
3. National Blood Transfusion Service
Centrally coordinated
Under the Ministry of Health
Cluster centers
Blood banks
Consultants, MOICs, MOs, PHIs MLTs/MLSs, NOs, Health Assistants, Lab orderlies
4. What do we do?
Select donors
Collect blood
Screen blood
Prepare and store components
Do Pre-transfusion testing
Issue blood and components
Investigate reactions
Clinical transfusion medicine
Therapeutic plasmapheresis/ PRP clinic
Other special investigations
5. Blood Donation
Even with all of today’s technology, there is no substitute for blood.
Blood is always needed for,
accident victims
cancer patients
blood disorder patients
surgery patients
Pre-mature, pre term babies
and many others…….
Someone has to give blood in order for someone to receive blood!
6. Who can donate?
Basic criteria
Age above 18 below 60 years
Weight above 50 Kg
Hemoglobin above 12.5 g/dl
Healthy
Safe life style
Donor selection criteria
1. Donor safety
2. Recipient safety
9. Donor screening
Blood group- ABO and Rh D
Transfusion transmittable infections
Virus Bacteria Parasites
Tested for
HIV 1& 2, Hep B, Hep C, Syphilis, Malaria
10. Who is a Blood donor
A hero
Voluntary nun-remunerated
Regular donor
Frequency of donation
whole blood 4 monthly
aphaeresis 2 weekly
Body recovers the Blood very quickly:
Blood plasma volume– within 24 - 48 hours
Red Blood Cells – in about 3 weeks
Platelets & White Blood Cells – within minutes
11. Cells
• Red cells
• White Cells
• Platelets
Plasma
• Fresh frozen plasma (FFP)
• Cryo-precipitate
Blood Components
12. Questions?
Assignment 01
1. What is a temporary deferral?
2. What is a permanent deferral?
3. Mention 5 temporary deferral and 5 permanent deferral criterias when
selecting blood donors?
Email the answers to mkrishnapillai@yahoo.com before 25.01.2021 with,
1. Your name
2. Roll number
14. Blood Grouping- EDTA sample
Major blood group system: ABO
Rh- D
Checking for Donor’s antigens and antibodies
Forward and reverse grouping- reciprocal relationship
15. Steps
Required Reagents:
Anti A, Anti AB, Anti B and Anti D antisera
A1 cells, B cells, O cells
Sample: EDTA- 1-2 ml
EDTA sample
Separate cells and plasma
Prepare 3-5% cell suspension
Tubes: 7, Centrifuge/ cell washer
Label as: Anti A, Anti AB, Anti B, Anti D, A cells, B cells, and O cells
18. Steps
Anti A Anti AB Anti B Anti D O cells
B cells
A1 cells
Forward grouping: 1 drop of antisera to each relevant tube and 1 drop of patient cells
Reverse grouping: 2 drops of plasma and one drops of relevant reagent red cells
plasma
3-5%
cells
Forward grouping Reverse grouping
19. Low spin- 500-1000g speed for 15 sec in the centrifuge and read.
Forward: 3+ or more, Anti D- 2+ or more
Reverse: 2+ or more
20.
21.
22. Blood
Group
Anti A Anti AB Anti B Anti D A1 cells B cells O cells
A+ + + 0 + 0 + 0
B+ 0 + + + + 0 0
AB+ + + + + 0 0 0
O+ 0 0 0 + + + 0
A Neg + + 0 0 0 + 0
B Neg 0 + + 0 + 0 0
AB Neg + + + 0 0 0 0
O Neg 0 0 0 0 + + 0
23. TTI
The provision of safe and efficacious blood and blood components for transfusion
or manufacturing use involves a number of processes.
From the selection of blood donors and the collection, processing and testing of
blood donations to the testing of patient samples, the issue of compatible blood
and its administration to the patient.
There is a risk of error in each process in this “transfusion chain” and a failure at
any of these stages can have serious implications for the recipients of blood and
blood products.
24. Screening for transfusion-transmissible infections (TTIs) to exclude blood
donations at risk of transmitting infection from donors to recipients is a critical
part of the process of ensuring that transfusion is as safe as possible.
Effective screening for evidence of the presence of the most common and
dangerous TTIs can reduce the risk of transmission to very low levels
Virus, bacteria, parasites
All donations must be screened
25. The microbial agents of importance to blood transfusion services are those that are
transmissible by blood transfusion and can cause morbidity and mortality in
recipients. In order to be transmissible by blood, the infectious agent or infection
usually has the following characteristics:
Presence in the blood for long periods, sometimes in high titres
Stability in blood stored at 4o ⁰C or lower
Long incubation period before the appearance of clinical signs
Asymptomatic phase or only mild symptoms in the blood donor, hencenot
identifiable during the blood donor selection process
26. WHO:
Mandatory screening to be done by all the nations:
1. HIV 1&2
2. Hep B
3. Hep C
4. Syphilis
Other infections: according to the country’s status
Sri Lanka: Malaria
28. One or a combination of markers of infection can be used to detect a particular
infection during the screening process. Various assay systems developed for
blood screening detect:
• Antibodies that indicate an immune response to the infectious agent
• Antigens that are produced by the infectious agent and indicate the
• presence of that agent
• Nucleic acid (RNA/DNA) of the infectious agent.
29. Types of screening assays
The main types of assay used for blood screening are:
Immunoassays (IAs):
— Enzyme immunoassays (EIAs)
— Chemiluminescent immunoassays (CLIAs)
— Haemagglutination (HA)/particle agglutination (PA) assays
— Rapid/simple single-use assays (rapid tests)
Nucleic acid amplification technology (NAT) assays.
Appropriate evaluation is required in selecting the type of assay for each TTI, based on critical
assay characteristics, such as sensitivity and specificity, as well as cost and ease of use.
30. Immunoassays
to detect antibody, antigen or a combination of the two
use of immobilized antigen which captures any specific antibody present in the
test sample (indirect IA)
31. Enzyme immunoassays (EIAs) and chemiluminescent immunoassays (CLIAs)
Most used assays
color generation in EIAs and measuring light produced by a chemical reaction in
CLIAs.
suitable for the screening of large numbers of samples and require a range of
specific equipment.
32. Particle agglutination assays
detect the presence of specific antibody or antigen in a test sample through the
agglutination of particles coated with the complementary specific antigen or
antibody respectively.
particles including red cells (haemagglutination) and inert particles such as
and latex.
do not involve multiple steps or need wash equipment
33. Rapid/simple single-use assays (rapid tests)
discrete, individual, disposable assays
based on a form of immunochromatography in which the added sample flows
down an inert strip and reacts with previously immobilized reagents
positive reaction is visualized as a dot or a band appearing on the device strip
simple-to-use formats
not suitable for screening large numbers of blood samples
34. Nucleic acid amplification technology
assays
detects the presence of viral nucleic acid, DNA or RNA, in donation samples
a specific RNA/DNA segment of the virus is targeted and amplified in-vitro
amplification step enables the detection of low levels of virus in the original
sample by increasing the amount of specific target present to a level that is easily
detectable.
performed on individual donations (ID) or on mini-pools (MP)
35. Selection of Assays
Each screening system has its advantages and limitations that should be taken into
consideration when selecting assays. Some limitations include:
The length of time following infection before the screening test becomes reactive
(window period)
Rates of biological false positives which may result in the wastage of donations
and unnecessary deferral of donors
The complexity of some systems that require automation.
36. HIV-1 and HIV-2: Serological markers:
— anti-HIV-1, + anti-HIV-2
— HIV p24 antigen (p24 Ag)
— Viral nucleic acid: HIV RNA.
Hepatitis B: Serological markers:
— Hepatitis B surface antigen
— Hepatitis B core antibody, in some situations
— Viral nucleic acid: HBV DNA.
Hepatitis C: Serological markers:
— HCV antibody
— HCV antigen
— Viral nucleic acid: HCV RNA.
Syphilis (Treponema pallidum):
— screening for specific treponemal antibodies-TPPA/TPHA
— Nonspecific- VDRL/RPR
Malaria-
— Thick and thin slides
— Malarial Ag/abs
37. Risk of transmitting infection to recipients has been drastically reduced in the past
decades, due to
Improved donor selection
Sensitive serologic screening assays
Application of viral inactivation procedures during manufacturing of plasma
products
38. Residual Risk
Major sources of remaining risk are:
1. Window period donation
2. Viral variants not detect by current assays
3. Immunosilent donor
4. Laboratory testing error
39. Residual Risk
The greatest threat to the safety of blood supply is the donation by seronegative
donors during the infectious window period
Window period donation account for 90% or more of the residual risk (Report of
the Interorganization Task Force on NAT Testing of Blood Donors, 2000)
40. Window Period
Period precedes the development of antibodies during the initial infection
Eclipse phase of the window period - the very initial phase after exposure when
virus replication is restricted to tissue sites and there is no detectable viraemia
Infectious phase of window period is after eclipse and before seroconversion
41.
42. Residual Risk
Risk of acquiring a transfusion-transmitted viral infection depends not only on the
length of specific window period but also on the incidence of the infection among
blood donors
43. Assignment 02
List out the TTI that are screened in Sri Lanka for all the blood donors.
What are the methods/screening assays used locally to screen these infections?
Email the answers to mkrishnapillai@yahoo.com before 25.01.2021 with,
1. Your name
2. Roll number