RESUMEN
OBJECTIVES: To study the main causes of pre-donation blood donors' deferral in a Brazilian blood bank. BACKGROUND: Blood donor selection is the most important process to maintain transfusion safeness. Pre-donation deferral aims to avoid the transmission of infectious diseases in the serological window, as well as to preserve blood donors' health. METHODS: This was a retrospective study undertaken in a single blood centre in Curitiba, Brazil, taking into account the number of blood donations per year, the number of annual donations by gender and the total number of blood donors deferred annually prior to blood donation from 1 January 2007 to 31 December 2016. RESULTS: Pre-donation blood donors' deferral ranged from 12·1 to 15·7% of donors. The main reason was related to donors' health (22·5-51·4%) followed by behavioural risk (17·6-29%). Issues related to blood donors' health diminished, and those related to behavioural risk increased with time. Blood donors deferred because of anaemia diminished with time and were more common in women than men (P < 0·001). CONCLUSIONS: Pre-donation blood donors' deferral ranges from 12·1 to 15·7% in our region. The most common cause was blood donors' health followed by behavioural risk. Anaemia was more common in women. Knowing this specific population better could avoid wasting blood bags and help to minimise costs and still maintain transfusion safety.