Analytical and Clinical Performance of VIDAS^® HIV DUO AG/AB Assay for Enhanced Early HIV Diagnosis

Background/Objectives: Early detection of HIV infection is critical for timely clinical management and prevention of transmission. Fourth-generation antigen/antibody assays improve early diagnosis by detecting p24 antigen prior to seroconversion. This study evaluated the analytical and clinical performance of the VIDAS^® HIV DUO AG/AB assay. Methods: A multicenter evaluation was conducted using WHO HIV-1 p24 standards, 50 HIV-1/HIV-2 culture supernatants representing diverse genotypes, 40 seroconversion panels, 634 HIV-positive clinical specimens, 6063 HIV-negative samples from four populations, and 272 potentially cross-reactive samples. Precision was assessed according to CLSI EP05-A3 guidelines. Performance was evaluated against VIDAS^® HIV DUO Ultra and contextualized with results reported for other fourth-generation assays. Results: VIDAS^® HIV DUO AG/AB showed a lower p24 antigen limit of detection (0.3 IU/mL) than VIDAS^® HIV DUO Ultra (0.5-0.6 IU/mL) and higher relative p24 reactivity across multiple genotypes. It enabled earlier detection in more than 30% of seroconversion panels, corresponding to a cumulative gain of 60 days versus VIDAS^® HIV DUO Ultra. Based on historical datasets, gains of up to 29 days were observed relative to reported performances of the ARCHITECT HIV Ag/Ab Combo and MAGLUMI HIV Ab/Ag Combi assays. All 634 HIV-positive clinical samples were detected, demonstrating broad genotype inclusivity within the diversity of HIV strains represented in this study. Specificity reached 99.95% (95% CI: 99.90-99.99%), with no cross-reactivity observed. Precision coefficients of variation were below 3.5%. Conclusions: The VIDAS^® HIV DUO AG/AB assay demonstrated high analytical sensitivity, early detection in seroconversion panels, broad genotype coverage, and excellent (>99.5%) specificity, supporting its use as a fourth-generation option for HIV screening in various clinical and epidemiological settings.