[en] BACKGROUND: In order to assess the implemented preventive measures of transfusion reactions (TR) and to make a study of residual reactions, we analyzed 516 TR reports from 14 hospitals, for three years since 1996 to 1998. METHODS: Clinical signs were classified according to seven etiologic categories. Systematic anti-erythrocyte and anti-leucocyte detection, as well as bacterial control of the returned bag were performed. RESULTS: The TR incidence is 3.7 per 1.000 products. Platelet concentrates (PC) provoke 7.4 TR per 1.000 transfusions, and red cell concentrates (RCC) 3.8. There are as many TR with apheresis platelets (AP), pre-storage leuco-depleted, as with random platelets, post-storage leuco-depleted, and as many with leuco-depleted RCC as with non leuco-depleted RCC. Leuco-depleted AP provoke more allergic reactions than other blood components. TR with AP are much more frequent in children than in adults. Plasma removal from AP before transfusion decreases reaction frequency. CONCLUSIONS: The lack in efficacy failure of pre-storage deleucocytation in TR prevention should be due to related patient factors. Etiology of AP allergic reactions deserves further study. PC suspension in synthetic medium before transfusion is an efficient means for RT decreasing. Hemovigilance system has to be improved so that all TR be reported.