Introduction: The acute phase of HIV infection is highly infectious due to the high viral load, and it is, therefore, important to diagnose infected individuals at this stage, as a way to prevent the occurrence of new infections. Most 4th generation HIV assays that detect acute infection are lab-based and require a cold chain to store the reagents. The identification of a rapid HIV test that allows the diagnosis in the acute phase, is relevant in low-income countries, such as Mozambique.

Objective: To evaluate the diagnostic accuracy of the 4th generation Determine HIV-1/2 Ag / Ab Combo compared to the 3rd generation rapid test and 4th generation enzyme immunoassay as gold standard namely Murex, Innotest and Enzygnost.

Methods: A cross-sectional study was conducted with samples of 998 pregnant women collected during their first visit to the prenatal consultation, in three health centres around Maputo city, Mozambique. In the Laboratory, samples were tested using the 4th generation Determine HIV-1/2 Ag / Ab Combo, the 3rd generation rapid test and 4th generation enzyme immunoassay as gold standard (Murex, Innotest and Enzygnost).

Results: The Determine HIV-1/2 Ag / Ab Combo test did not detect antigens in all samples of participants with acute HIV infection (11/11), resulting in a 0% test sensitivity. One positive antigen sample in the evaluated rapid test, could not be confirmed by the viral load test or EIA antigen and counted as false positive. The specificity of the antigen test by determination of the HIV-1/2 Ag / Ab Combo test was therefore calculated in 99.9% (969/970).

Conclusions: The study did not demonstrate any benefit of using the 4th generation rapid test, Determine HIV-1/2 Ag / Ab Combo on existing 3rd generation rapid tests. There is a need for further development of rapid and reliable trials for the diagnosis of individuals with acute HIV in resource-limited settings with high HIV prevalence.

Keywords: acute infection, HIV, rapid test.