Original Article Diagnostic Immunology Reduction of the HIV Seroconversion Window Period and False Positive Rate by Using ADVIA Centaur HIV

Background: Early diagnosis of HIV infection reduces morbidity and mortality. Fourth-gen-eration HIV detection assays are more sensitive because they can detect p24 antigen as well as anti-HIV antibodies. In this study, we evaluated the performance of a new fourth-generation ADVIA Centaur HIV antigen/antibody combo (CHIV) assay (Siemens Health-care Diagnostics Inc., USA) for early detection of HIV infection and reduction of false posi-tive rate. Methods: Four seroconversion panels were included. The third-generation ADVIA Centaur HIV 1/O/2 enhanced (EHIV) assay (Siemens Healthcare Diagnostics Inc., USA) and fourth-generation CHIV assay were used to test each panel for HIV infection. The presence of an-tigen was confirmed using HIV p24 antigen assay. To evaluate false-positivity and specific-ity, 54 HIV false-positive and HIV-negative serum samples from 100 hospitalized patients and 600 healthy subjects were included. Results: Compared to the EHIV assay, the CHIV assay had a shorter window for three of the seroconversion panels: a difference of 10 days and two bleeds in one panel, and 4 days and one bleed in the other two panels. Only 34 of the 54 (63%) samples known t