RESUMO
BACKGROUND: Screening blood donations for human immunodeficiency virus 1/2 (HIV-1/2) infection in blood centers is often done with a highly sensitive 3rd-generation immunoassay which may cause false-positive results. Donations found repeatedly reactive (RR) are discarded regardless of negative HIV-1/2 nucleic acid testing (NAT) and confirmatory assays results. These donors are notified and deferred if RR in a subsequent donation. We evaluated the introduction of a secondary 4th-generation serological assay to the overall algorithm performance. METHODS: All donations collected between January 2016 and May 2018 (574,338) were screened using 3rd-generation immunoassay (PRISM HIV O Plus) and NAT (Procleix Ultrio/Ultrio Elite). Serology RR donations were tested with 4th-generation Architect HIV Ag/Ab Combo and Vidas HIV Duo Ultra and a confirmatory assay (Geenius HIV-1/2). RESULTS: The two 4th-generation assays found that 86% (179/209 on Architect) and 94% (182/193 on Vidas) of the 3rd-generation immunoassay RR were negative for HIV-1/2, which were also negative by confirmatory assay. Only 14% (30/209 on Architect) and 6% (11/193 on Vidas) that were 3rd-generation HIV-1/2 RR required confirmation, of which eight donors were confirmed as HIV positive. The probability of missing an HIV-1 infected donor by this algorithm is one in a million RR cases. CONCLUSION: The introduction of a two-step serological screening algorithm in blood centers whereby 4th-generation assay will be performed for all 3rd-generation RR blood donors will reduce the number of donations requiring confirmation, save time and money, and most importantly, reduce the number of discarded blood donations and allow re-entry processes.
