Screening the Tissue Donor for Infectious Agents

Like all substances of human origin, tissues are capable of transmitting infectious agents from donor to recipient. The screening of tissue donors for blood-borne infectious agents helps minimise this risk. To ensure the reliability and accuracy of screening a number of critical elements need to be considered. The quality of the samples provided needs to be assured, especially when tissues are collected from deceased donors. Although the core range of transmissible infectious agents is the same for blood and tissue donors, additional markers of some infectious agents may be included for tissue donors. The screening strategy and algorithms used for tissue donors may differ from those applied to blood donations. The number of tissue donors and the retrieved tissues is often less than the numbers required, and unnecessary loss of tissue donations because of non-specific screen reactivity must be minimised. This can be achieved through careful and scientifically based selection of the screening algorithm used. In addition, effective confirmatory testing of all screen reactive samples should be performed, with good confirmatory testing it is quite appropriate to consider releasing screen reactive tissues based on confirmatory results. To ensure the algorithms do provide the required outcomes, the most suitable assays must be selected, ensuring the highest possible sensitivity without loosing too much specificity. However, as with all substances of human origin, zero risk is not achievable, and even after reliable and high quality screening, some residual risk, albeit very low, remains.