Immunofluorescent antibody test as additional confirmation of HIV-1infection: seven years of use at the Colombia National Institute of Health

Abstract

A team at the Colombian National Institute of Health (INS) has demonstrated the usefulness and suitability of the Immunofluorescent Antibody Test (IFAT) as a confirmatory assay for HIV-1. The assay followed a flow chart method recommended by the Pan American Health Organization (PAHO) and the Federal Center for AIDS of Canada. The specificity of the IFAT assay (IFI-VIH1- INS) for 925 serum samples was 100% when compared with two different Western blot (WB) assays. The IFI-VIH1-INS showed a sensitivity of 61% across 6,137 human sera. Although its specificity is excellent, the sensitivity of the IFI-VIH1-INS assay is slightly lower than other IFAT assays (41% of 975 samples were indeterminate in both IFAT assays and WB tests). After implementation of this assay in more than 6,000 serum samples between 1993 and 2000, the INS saved more than Col $340,000,000 or US $170.000 in its HIV1 testing program.