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Transfusion Medicine- An Introduction and Basics of Screening Blood Donors
Transfusion medicine is a multidisciplinary field focused on the safe use of blood and blood products for disease treatment and prevention, involving donor selection, blood collection, screening, and compatibility testing. Blood is essential for various medical needs including trauma, cancer, and surgery, and strict donor criteria and screening protocols are necessary to ensure the safety of transfusions by preventing transmission of infectious diseases. Key processes include testing for transfusion-transmissible infections, using various assays to ensure blood safety and minimize residual risk associated with window period donations.
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Transfusion Medicine- An Introduction and Basics of Screening Blood Donors
- 1. Transfusion Medicine An Introduction MATHURANGEKRISHNAPILLAI MBBS, DTM, MD TRANSFUSION MEDICINE (ACTING)CONSULTANT TRANSFUSION PHYSICIAN
- 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 TransfusionService 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 wedo? 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 Evenwith 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? Basiccriteria 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
- 7. Blood donation process Education Donor declaration Donor selection and Haemoglobin estimation Donor registration Blood collection
- 9. Donor screening Bloodgroup- ABO and Rh D Transfusion transmittable infections Virus Bacteria Parasites Tested for HIV 1& 2, Hep B, Hep C, Syphilis, Malaria
- 10. Who is aBlood 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 [email protected] before 25.01.2021 with, 1. Your name 2. Roll number
- 13. Screening Blood Donors Donortesting, 1. Blood group 2. Transfusion Transmitted Infections
- 14. Blood Grouping- EDTAsample Major blood group system: ABO Rh- D Checking for Donor’s antigens and antibodies Forward and reverse grouping- reciprocal relationship
- 15. Steps Required Reagents: AntiA, 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
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- 18. Steps Anti A AntiAB 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
- 22. Blood Group Anti A AntiAB 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 provisionof 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 fortransfusion-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 agentsof 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 screeningto 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
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- 28. One or acombination 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 screeningassays 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 detectantibody, 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 amplificationtechnology 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 Eachscreening 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 andHIV-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 transmittinginfection 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 Majorsources 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 Thegreatest 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 Periodprecedes 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
- 42. Residual Risk Riskof 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 Listout 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 [email protected] before 25.01.2021 with, 1. Your name 2. Roll number
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