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17 - Quality in the screening of donations for transfusion-transmissible infections
- from Section 2 - Selection and testing
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- By John A. J. Barbara, Visiting Professor in Transfusion Microbiology, University of the West of England, Bristol, UK, Alan D. Kitchen, Head, National Transfusion Microbiology Reference Laboratory, NHS Blood and Transplant, Colindale, London, UK
- Edited by John A. J. Barbara, University of the West of England, Bristol, Fiona A. M. Regan, Marcela Contreras, University of the West of England, Bristol
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- Book:
- Transfusion Microbiology
- Published online:
- 12 January 2010
- Print publication:
- 24 April 2008, pp 217-226
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Summary
Introduction
The field of transfusion microbiology has developed rapidly over the last 20 years. However, not only has the field developed in terms of the understanding of the biology and science of the infectious agents, the advent of automated mass screening systems, and the increased general focus on the microbial safety of blood and blood products, but importantly the overall quality – the reliability and effectiveness of screening has improved significantly. This quality improvement has come from a number of sources:
The identification of those transmissible infectious agents of most concern for transfusion
A more detailed and comprehensive understanding of the biology of transmissible agents
The development of sensitive assays for transmissible agents
The improvements in assay design, including the inclusion of specific features to monitor the step-by-step performance of the assay
The introduction of quality management systems into blood transfusion services (BTSs)
The development of appropriate automation
The introduction of licensing/accreditation of BTSs
The introduction of haemovigilance systems.
Overall, it is the amalgamation of the above elements into a single seamless system that has resulted in the current overall high level of safety of the blood supply in most countries with developed health care systems. Nonetheless, it must be understood that these systems are not always as robust as one would wish, and vigilance is necessary to ensure that quality standards are maintained. In addition, the potential threat of new, as yet unidentified, agents must not be forgotten.
12 - Confirmatory testing and donor re-admission
- from Section 2 - Selection and testing
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- By Alan D. Kitchen, Head, National Transfusion Microbiology Reference Laboratory, NHS Blood and Transplant Colindale, London, UK, Brian C. Dow, Consultant, Clinical Microbiologist; Head, Scottish National Blood Transfusion Service, National Microbiology Reference Unit, West of Scotland, Transfusion Centre, Glasgow, UK
- Edited by John A. J. Barbara, University of the West of England, Bristol, Fiona A. M. Regan, Marcela Contreras, University of the West of England, Bristol
-
- Book:
- Transfusion Microbiology
- Published online:
- 12 January 2010
- Print publication:
- 24 April 2008, pp 173-182
-
- Chapter
- Export citation
-
Summary
Introduction
The major focus in ensuring the microbiological safety of the blood supply relies heavily on the primary screening of donated blood. Although routine donor screening assays are highly sensitive, this sensitivity is often achieved at the expense of specificity (0.05–0.5%) (Dow, 2000).
Blood donations found to be initially reactive at donor testing sites should be repeat tested in duplicate. Should any of the repeat tests result in reactivity, the donation is classified as ‘repeatedly reactive’, the donor is flagged on the donor database and samples are submitted to the designated national reference laboratory or other designated facility. Regardless of confirmatory test results, the donation and all its associated components will be excluded from transfusion.
Throughout the world, blood services have differing policies with regard to confirmation of microbiology reactive donations. Most developed countries' services are capable of performing adequate confirmation of reactive donations. However, some services use an alternative strategy of reporting reactivity directly to the donors, often resulting in considerable donor anxiety and potential personal expense to reach a confirmatory conclusion. Obviously, in areas of high endemicity, there is a higher predictive value associated with a repeat reactive result and in this situation, simpler confirmatory algorithms can be utilized. Generally though, in developed countries, donors have relatively low prevalences of infection and therefore more complex confirmatory algorithms, like those described in this chapter, are often necessary before notification to the apparently healthy volunteer donor.