Comparison of the performance of rapid HIV tests using samples collected for surveillance in Mozambique

Mozambique had low HIV prevalence until the mid‐1990s, but recent data indicate increasing rates. There is little information on HIV‐2. Therefore, HIV seroprevalence was assessed among pregnant women and field‐ready HIV diagnostic strategies were evaluated. A total of 6,930 samples collected by three health centers from 2002 to 2005 were tested on site by nurses with two simple/rapid tests, Determine HIV‐1/2 (Abbott Laboratories; screening) and Uni‐Gold HIV (Trinity Biotech; confirmation), which is the national HIV testing strategy. The prevalence of HIV was 14.0% (2002), 17.8% (2003), 16.5% (2004), and 20.2% (2005). A subset of 888 samples collected 2003 was sent to the Central Microbiology Laboratory, Maputo for evaluation of tests and testing strategies. The assays included for comparison were Capillus HIV‐1/HIV‐2 (Trinity Biotech), DoubleCheckGold HIV‐1&2 (Orgenics) and Enzygnost Anti‐HIV‐1/2 Plus (Behringwerke, reference ELISA). Confirmation of reactive samples was done by Uni‐Gold HIV and ImmunoComb II HIV‐1&2 BiSpot (for HIV type differentiation). The Capillus HIV‐1/ HIV‐2 + ImmunoComb II HIV‐1&2 BiSpot combination was the gold standard. The sensitivity of the rapid/simple screening assays (Determine HIV‐1/2, DoubleCheckGold HIV‐1&2) was 100% (N = 160) and their (initial) specificities were 99.6% and 99.7%, respectively. Repeated testing and combinations of assays increased the specificity. Four suspected cases of recent seroconversion were found. Together with the increasing prevalence rates, this may indicate that Mozambique is a high‐incidence area, although further studies are needed to confirm this. Testing strategies for on‐site screening and confirmation based on the combination of Determine HIV‐1/2, Uni‐Gold HIV and DoubleCheckGold HIV‐1&2 are well suited for local field use. J. Med. Virol. 81:1991–1998, 2009. © 2009 Wiley‐Liss, Inc.