Rapid and simple screening and supplemental testing for HIV-1 and HIV-2 infections in west Africa.

OBJECTIVE: To evaluate a combination of rapid tests as a strategy for screening and supplemental testing of serum for HIV-1 and/or HIV-2 antibodies.

DESIGN: Cross-sectional evaluation.

SETTING: Projet RETRO-CI, an AIDS research project in Abidjan, Côte d'Ivoire.

METHODS: Serum specimens were collected from 1000 consecutive women giving birth in an Abidjan maternal and child health centre and from 185 hospitalized patients. All serum specimens were tested for HIV-1 and HIV-2 antibodies by whole-virus enzyme immunoassay; repeatedly reactive specimens were further tested by virus-specific Western blot and synthetic peptide-based tests. This was the reference strategy against which the algorithm under evaluation was compared. All specimens were subsequently tested by a mixed (HIV-1 and HIV-2) recombinant antigen-based test (Abbott Testpack), followed, if positive, by a rapid synthetic peptide-based test (Genetic Systems Genie) as a supplemental test.

RESULTS: According to the reference strategy the prevalence of HIV-1 and/or HIV-2 infection was 13% among the pregnant women and 78% among the hospitalized patients. Compared with the reference strategy, the combination of rapid tests was associated with a sensitivity of 99.6%, a specificity of 99.9%, and positive and negative predictive values of 99.6 and 99.9%, respectively. Four per cent of HIV-2-positive and 1% of HIV-1-positive specimens were considered dually reactive by the rapid test combination.

CONCLUSIONS: Synthetic peptide-based tests provide an alternative to Western blots for supplemental testing for HIV-1 and HIV-2. This combination of rapid tests offers performance characteristics comparable to an enzyme immunoassay and Western blot-based strategy, without requiring running water, electricity, or a well-developed laboratory. High-quality serodiagnosis of HIV-1 and HIV-2 infections is possible at the most peripheral levels of the health-care system in developing countries, the limiting factors being the costs of tests and training of staff.