RESUMO
BACKGROUND AND OBJECTIVES: The purpose of this article was to describe the experience of screening for human immunodeficiency virus (HIV) p24 antigen (p24Ag) in blood donors, in four Brazilian Blood Banks, and to report the detection of the first window-period donation. MATERIALS AND METHODS: During 61 months (May 96 to June 01), 103 470 consecutive donations were screened for HIV p24Ag using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Testing was carried out in accordance with the instructions supplied with the kits. RESULTS: Fifty-eight repeatedly reactive samples were identified [0.056% of the total; 95% confidence interval (95% CI): 0.042-0.070]. Ten of the 58 were confirmed as p24Ag positive after neutralization (0.010%; 95% CI: 0.004-0.016), nine of the 10 (0.009%; 95% CI: 0.003-0.014) were also HIV antibody positive and only one (0.001%; 95% CI: 0-0.003) was HIV antibody negative. CONCLUSIONS: In this setting the rate of sole p24Ag-positive donations was one in 103 740. This figure corresponds closely with the previously estimated yield of one in 87 796 donations. The yield of HIV p24Ag+ : Ab- has been previously estimated in our centres to be 1 : 87 796 donations, a value similar to that observed in actual practice.
