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.