Early detection of human immunodeficiency virus infection using third- andfourth-generation screening assays

Early detection of infection with human immunodeficiency virus (HIV) is cri tical for clinical diagnosis and treatment of patients, as well as for ensu ring the safety of blood transfusion products. Recently, a number of fourth -generation HIV screening assays have been developed that offer increased s ensitivity over earlier tests by combining detection of anti-HIV antibodies with detection of the p24 viral antigen. Previously, six different HIV ass ays were compared against a broad range of 30 seroconversion panels. In the present study, three of the newer fourth-generation assays were tested tog ether with three of the third-generation HIV antibody-only assays. This ext ensive 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 D uo 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.