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 ant ibodies. Design: Cross-sectional evaluation. Setting: Projet RETRO-Cl, an AIDS research project in Abidjan, Cote d'Ivoire. Methods: Serum sp ecimens were collected from 1000 consecutive women giving birth in an Abidjan maternal and child health centre and from 185 hospitalized pat ients. 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-ba sed 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 T estpack), followed, if positive, by a rapid synthetic peptide-based te st (Genetic Systems Genie) as a supplemental test. Results: According to the reference strategy the prevalence of HIV-1 and/or HIV-2 infecti on was 13% among the pregnant women and 78% among the hospitalized pat ients. 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%, res pectively. Four per cent of HIV-2-positive and 1% of HIV-1-positive sp ecimens 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 combi nation of rapid tests offers performance characteristics comparable to an enzyme immunoassay and Western blot-based strategy, without requir ing running water, electricity, or a well-developed laboratory. High-q uality serodiagnosis of HIV-1 and HIV-2 infections is possible at the most peripheral levels of the health-care system in developing countri es, the limiting factors being the costs of tests and training of staf f.