RESUMEN
BACKGROUND: Routine screening for viral infections at blood donation is important to avoid transfusion-transmitted infections. It also offers an opportunity to detect an asymptomatic infection. OBJECTIVE: To study changes in serology positivity for viral infections (B and C hepatitis, HTLV-1/2, and HIV) at blood donation in a blood bank from Southern Brazil, comparing two periods of 5 years: the period from 2013 to 2017 with the period from 2018 to 2022. In addition, data on the donor fidelity rate during the studied period were sought. METHODS: Retrospective study using data from 2013 to 2022 from a single blood center electronic database from Curitiba, Southern Brazil. RESULTS: A significant drop in positive serology for all studied viruses was observed: highest in HIV (OR=0.39; 95% CI=0.27-0.57) and lowest in total anti HBc (0.56; 95 CI=0.50-0.63). Anti HBc serology became more commonly seen in women in the period of 2018-2022 when compared to men. No changes in the distribution of positive serology according to donors' ages were observed. Loyalty rates had a median of 70%, with the lowest being 60% in 2013, while the highest was 73% in 2018 and 2022. CONCLUSION: A significant reduction in discarded blood bags due to viral serology was observed when the period of 2013-2017 was compared to 2018-2022 on this blood bank; the highest reduction was observed in HIV serology and the lowest in HBc serology, which became more common in women in the second period. High rates of donor fidelity were observed during the period studied.