BACKGROUND AND OBJECTIVES: Recent studies have suggested that potentially infectious donations provided during the antibody-negative 'window' phase of hepatitis C virus (HCV) infection may be identified by testing for viral RNA or HCV core protein. We therefore evaluated the performance of an HCV antigen enzyme-linked immunosorbent assay (ELISA) for identification of window-phase donations and for prospective screening of blood donors. MATERIALS AND METHODS: One-hundred and twenty-eight archived plasma donations containing HCV RNA, but lacking antibody to HCV (anti-HCV), were tested by using the HCV antigen ELISA, together with 9951 freshly collected serum and plasma specimens from blood donors. RESULTS: HCV core antigen was detected in 94% (120/128) of window-phase plasma donations. Overall specificity in freshly collected blood donor specimens was 99.74%. Two putative window-phase donations containing HCV core protein and viral RNA were identified from paid plasma donors by prospective testing with the HCV antigen ELISA. CONCLUSION: These results indicate that an HCV antigen ELISA can identify almost all (94%) of viraemic donations given during the seronegative window phase of infection. The performance of the HCV antigen ELISA appears to be suitable for large-scale screening of blood donations.
BACKGROUND AND OBJECTIVES: Recent studies have suggested that potentially infectious donations provided during the antibody-negative 'window' phase of hepatitis C virus (HCV) infection may be identified by testing for viral RNA or HCV core protein. We therefore evaluated the performance of an HCV antigen enzyme-linked immunosorbent assay (ELISA) for identification of window-phase donations and for prospective screening of blood donors. MATERIALS AND METHODS: One-hundred and twenty-eight archived plasma donations containing HCV RNA, but lacking antibody to HCV (anti-HCV), were tested by using the HCV antigen ELISA, together with 9951 freshly collected serum and plasma specimens from blood donors. RESULTS:HCV core antigen was detected in 94% (120/128) of window-phase plasma donations. Overall specificity in freshly collected blood donor specimens was 99.74%. Two putative window-phase donations containing HCV core protein and viral RNA were identified from paid plasma donors by prospective testing with the HCV antigen ELISA. CONCLUSION: These results indicate that an HCV antigen ELISA can identify almost all (94%) of viraemic donations given during the seronegative window phase of infection. The performance of the HCV antigen ELISA appears to be suitable for large-scale screening of blood donations.