Early Detection of Human Immunodeficiency Virus Infection Using Third- and Fourth-Generation Screening Assays

 Early detection of infection with human immunodeficiency virus (HIV) is critical for clinical diagnosis and treatment of patients, as well as for ensuring the safety of blood transfusion products. Recently, a number of fourth-generation HIV screening assays have been developed that offer increased sensitivity over earlier tests by combining detection of anti-HIV antibodies with detection of the p24 viral antigen. Previously, six different HIV assays were compared against a broad range of 30 seroconversion panels. In the present study, three of the newer fourth-generation assays were tested together with three of the third-generation HIV antibody-only assays. This extensive analysis highlights (i) the importance of p24 antigen detection for early diagnosis, (ii) the improved sensitivity of fourth-generation assays over antibody-only tests, and (iii) the superior performance of the Vidas Duo assay, which allows reduction of the diagnostic window by up to 2 weeks. Finally, the results emphasize the detection limitations of the different assays and suggest improvements for future HIV screening assays.