The Canadian blood donor health assessment questionnaire: lessons from history, application of cognitive science principles, and recommendations for change.

Over the last 20 years, the Canadian Blood Services' (CBS) Donor Health Assessment Questionnaire (DHAQ), used to screen prospective blood donors to determine their eligibility, has grown in complexity and length. Its growth is inextricably linked to the evolution of the environment within which CBS operates from unregulated collection and distribution of labile blood products to a fully regulated environment and to the need to satisfy both Health Canada and US Food and Drug Administration (FDA) requirements. Within this context, the development of the CBS DHAQ has been characterized by addition of questions and items without any periodic reevaluation of the need for retaining existing questions and/or items. In this review, we apply principles from cognitive science relating to how people think when answering questionnaires to the situation of blood donors completing the DHAQ. We show that some items that were added at different times in separate questions, for reasons that were historically relevant, could be now asked more simply with a single question. The historical development of the DHAQ, resulting in the condensing of many items into lists, the use of complex wording, and the sheer number of items included in the questionnaire make accurate retrieval of information from the donor's memory difficult. Thus, we believe that redesigning the DHAQ will improve the quality and accuracy of the donors' answers to screening questions.