We evaluated a two-rapid-test serial algorithm using the Determine and Genie II rapid assays, performed on-site in four peripheral laboratories during the French Agence Nationale de Recherches sur le SIDA ( , respectively. The specificities were 98.4% (95% CI, 96.9 to 99.3%) and 100% (95% LL, 99.3%), respectively. All serological assays gave concordant results for infections with single types. By contrast, for samples found to be infected with dual HIV types by the Genie II assay, dual reactivity was detected for only 37 samples (52.1%) by WB assays, 34 samples (47.9%) by the Peptilav assay, and 23 samples (32.4%) by the monospecific ELISAs. For specimens with dual reactivity by the Genie II assay, the rates of concordance between the real-time PCR assays and the serological assays were 25.7% for the Genie II assay, 82.9% for the Peptilav assay, 74.3% for WB assays, and 80% for the homemade ELISAs. Our algorithm provided high degrees of sensitivity and specificity comparable to those of ELISAs. Even if they are rare, women identified by the Genie II assay as being infected with HIV-1 and HIV-2 mostly appeared to be infected only with HIV-2.Human immunodeficiency virus (HIV) antibody testing is a critical step that allows the implementation of effective prevention and care interventions in HIV-infected individuals. Simple voluntary counseling and testing (VCT) approaches are increasingly required, especially in situations in which the rapid identification of HIV infection is warranted, such as in pregnant women during gestation and in the peripartum period (3, 6, 13). For instance, among pregnant women attending antenatal clinics in Côte d'Ivoire, among whom the prevalence of HIV infection is estimated to be 10%, the increasing implementation of low-cost interventions to reduce mother-to-child transmission (MTCT) with short antiretroviral regimens has created new demands for VCT (22).For this purpose, the use of standard enzyme-linked immunosorbent assays (ELISAs), designed for batch testing, followed by confirmatory Western blot (WB) tests, if necessary, is now considered time-and money-consuming (5, 23). Sophisticated equipment (such as automatic pipettes, incubators, washers, and readers) must be available, is costly to purchase and maintain, and must be located near clean water and a reliable supply of electricity. The validity of the results obtained by these techniques strongly depends on the skills of the technicians, and their interpretation requires skills training and supervision. These conditions are often lacking in sub-Saharan Africa, at least in district-level hospitals. Finally, given the important delay between HIV antibody testing by standard procedures and the availability of results, a significant number of people do not return for posttest counseling (21).