A major goal of transfusion medicine practice has been to reduce the risk of transfusion-transmitted infection to as low a level as possible [1,2]. In order to approach the desired level of zero risk from transfused allogeneic blood, multiple layers of safety are needed. Methods used in attempting to maximize safety from donated allogeneic units include donor selection criteria, donor medical history interview, the confidential unit exclusion (CUE) option, donor deferral registries, laboratory testing of donated units, donor initiated telephone call backs, and modification of the blood unit after collection, either by leukocyte removal or pathogen inactivation [3,4].
In addition to these recipient protections, the evaluation of each prospective blood donor includes procedures to assure that the donor will not suffer any adverse reactions from the donation itself or from hematopoietic growth factors employed to facilitate donation [5,6].
This discussion will provide an overview of the procedures involved in blood donor screening. Specific aspects of blood donor screening including medical history and laboratory testing are presented separately. (See "Blood donor screening: Medical history" and "Blood donor screening: Laboratory testing".)
ESTABLISHMENT OF PROCEDURES
When it is first suspected that an infectious agent may be transmitted by transfusion, the initial response is to develop donor deferral policies using epidemiologic data derived from high risk populations [3,5]. After this initial step, subsequent review and debate often leads to the nationwide implementation of a particular donor screening procedure following recommendations of the US Food and Drug Administration (FDA) and/or the AABB (formerly the American Association of Blood Banks) [7,8]. Once implemented, screening procedures tend to become permanent due to the current regulatory, political, and legal climate, even if their efficacy cannot be established.
For many diseases, such as Creutzfeldt-Jacob disease (CJD), which has not been proven to be transfusion transmitted, variant CJD, babesiosis, and malaria, non-laboratory donor screening procedures are the only method available for increasing transfusion safety [9-12]. In contrast, for those infectious diseases for which routine blood donor testing is performed (HIV, HTLV, hepatitis C virus, hepatitis B virus, and syphilis), the importance of non-laboratory donor screening procedures relates to their ability to identify some potentially infectious donors during the infectious, seronegative window period (table 1) [2,13].