Discriminatory capacity between HIV-1 and HIV-2 of the new rapid confirmation assay Geenius.

The currently used HIV confirmatory assays, Western blot and line immunoassay, are costly, complex and time-consuming. There is a need for cheaper, simpler and faster assays for use in high- and low-resource settings. Furthermore, it is necessary to differentiate between HIV-1 and HIV-2 infection due to differences in disease progression, monitoring and treatment options. Because the new Geenius HIV 1/2 Confirmatory Assay (Bio-Rad) has a European Community (CE) label, this study focused on its differentiation capacity using serum/plasma specimens from established HIV-1, HIV-2 and HIV untypable infections from the AIDS Reference Laboratory (ARL) of the Institute of Tropical Medicine (ITM) in Belgium. The results were compared with ARL's standard algorithm for diagnosis of HIV-infection and the new interpretation criteria for discrimination of the INNO-LIA HIVI/II Score, Fujirebio, Ghent, Belgium (LIA). The study showed a performance comparable to that of the reference LIA, with an overall sensitivity of 99.3% and specificity of 98%. Differentiation capacity was much better for the Geenius assay, with 93.8% of samples identified correctly as HIV-1 or HIV-2. When the new interpretation criteria for the LIA were used, the differentiation capacity of LIA increased to 98.5%. The results show that the Geenius assay is a reliable and fast alternative for the confirmation and differentiation of HIV-1 and HIV-2 infection in resource-rich and poor settings.