Blood donor candidates are submitted to clinical and serological screening to minimize the risk of disease transmission. One of the limitations of this screening is the immunological window, a period that may contribute to the transfusion of contaminated blood. The aim of this study was to evaluate self-exclusion rates related to age, gender, marital status, race, type of donation, annual variations in self-exclusion and the efficacy of self-exclusion to prevent the transfusion of contaminated blood. A retrospective study was conducted and the data were analyzed using the chi-square test, odds ratio and linear regression. Of the 176,097 blood bags collected at the Uberaba Regional Blood Center (HRU) between 1996 and 2006, 2.72% were discarded due to self-exclusion. There was a predominance of first-time, unmarried, non-white male donors over the age of 29 years old (p<0.0001). An inverse association was observed between long-term commitment and self-exclusion, suggesting that the higher the return rate, the lower the incidence of self-exclusion. Positive serology for HIV1 (0.35%) and HIV2 (0.23%) was significantly higher among self-exclusion donors (p<0.0001), a fact not observed for HCV (0.52%) (p=0.24). The percentages of these three diseases were 0.15%, 0.03% and 0.41%, respectively among donors not initiating self-exclusion. The higher frequency of self-exclusion among unmarried, non-white male donors over the age of 29 partly agrees with the donor profile of HRU. The decline observed from 1996 to 2001 might be explained by behavioral factors, such as the creation of anonymous testing centers and an increase in the long-term commitment of donors over the years. The higher frequency of positivity among self-exclusion donors and only three seroconversions in subsequent donations support the importance of this tool to reduce the risk of contamination due to the immunological window.
Blood donation; self-exclusion; positive serology; security transfusion
