[Alternative strategy for the diagnosis of HIV infection in sub-saharan Africa. Value of the sequential combination of the ELISA test and a 2nd generation rapid test].

The "conventional" algorithm for HIV testing based on the confirmation of all positive anti-HIV screening reactions by Western blot requires sufficient laboratory facilities and is expensive, that limits its use in developing countries, such as in subsaharian Africa. The apparition of second and third generation screening ELISA which are very sensitive and specific, as well as the development of rapid tests which are simple, visually read, and sufficiently sensitive and specific, has permitted the design of "alternative" strategy for HIV testing utilizing the association of 2 ELISA and/or rapid tests, in order to limit the use of a confirmatory assay. Alternative strategies are less expensive, yield generally very high sensitivity and specificity, and have proved to be valuable for African countries. In this study, 5 alternative strategies, using different associations of two second generation screening tests, one classical ELISA (Genelavia mixt) and one rapid test (Test PACK HIV-1/HIV-2 AB) have been retrospectively evaluated in the field in Bangui, Central African Republic, with a panel of 130 sera (prevalence of HIV infection: 42.7%). The strategy using two sequential screening tests (Test Pack HIV-1/HIV-2 AB following by Genelavia mixt) with the confirmation of discordant results by Western blot permitted to diagnose HIV-1 infection in Bangui with a sensitivity, a specificity and a positive predictive value of 100%, and to reduce the cost of more than 50% in comparison with the conventional strategy. Such an alternative strategy could be useful for the individual notification of HIV serology in Bangui.