Blood Donation Knowledge Questionnaire (BDKQ-Brazil): analysis of items and application in primary healthcare users

BACKGROUND: To present the results of the application of the Blood Donation Knowledge Questionnaire in a large and representative sample of users of primary care services in order to extend the evaluation of the metrics of the items and to assess knowledge about blood donation in association with sociodemographic variables. METHOD: The Blood Donation Knowledge Questionnaire is composed of 24 items based on blood donation requirements of the Brazilian Ministry of Health and on some popular beliefs and concepts of the Brazilian population regarding the blood donation process. Data collection was carried out in 12 healthcare facilities of Ribeirão Preto, São Paulo. The analysis of items was performed using classical test theory with associations being assessed using the multivariate Tobit regression model. RESULTS: A total of 1055 individuals participated (79.7% females and a mean age of 40.6 years). Previous blood donation was reported by 246 (23.3%) participants, 669 (63.4%) had never donated, and 140 (13.3%) reported being ineligible to donate blood. This questionnaire is comprised of items considered easy-to-understand, with a facility level of medium to high and generally an adequate capability of discrimination. Higher means of correct answers were detected among females, individuals with more schooling, and subjects who had already donated blood. CONCLUSION: The Blood Donation Knowledge Questionnaire is an instrument that aims to measure some general aspects of knowledge regarding blood donation and can be used in different contexts. There is evidence that knowledge of primary healthcare users regarding blood donation is correlated to sex, educational level, and previous blood donation.