Evaluation of the sensitivity and specificity of six HIV combined p24 antigen and antibody assays.

Abstract In this study, we evaluated the performance of six HIV combined p24 antigen and antibody (Ag/Ab) assays versus two third-generation anti-HIV antibody assays. The assays were evaluated using p24 antigen panel of 31 HIV-1 subtypes ( n  = 124), 25 HIV-1 seroconversion panels ( n  = 176), HIV-1 antibody positive samples including group M subtypes and group O ( n  = 559), HIV-2 positive samples ( n  = 110), and unselected HIV negative samples from four French private laboratories ( n  = 1005). The results showed that overall HIV combined Ag/Ab assays present better performance, when compared to antibody-only assays. However, some differences were observed in the sensitivity of the six HIV combined Ag/Ab assays evaluated. The AxSYM and Murex Combo assays had the best sensitivity score in this study and reduced the window period by 2.0–2.35 days relative to antibody only assays and 1–2.17 days relative to the other combined Ag/Ab assays. Among combined HIV Ag/Ab assays, Genscreen Plus and AxSYM Combo presented the highest specificity, with 99.9% and 99.8%, respectively.