Diagnosis of hiv infection with instrument-free assays as an alternative to the elisa and western blot testing strategy: An evaluation in central africa

The efficiency of an alternative instrument-free testing strategy was evaluated using a membrane-based rapid screening assay (HIVCHEK and its new version HIVCHEK1+2) in serial combination with a particle agglutination assay (SERODIA-HIV). Among 1054 Zairian individuals at high risk of HIV infection 573 were Western blot-positive for HIV-1 (54-5%) and none were Western blot-positive for HIV-2. In this group the sensitivities of the serial combination HIVCHEK plus SERODIA-HIV and HIVCHEK1+2 plus SERODIA-HIV were 98.1 and 98.2% respectively and the specificities were 99.6 and 99.5% compared with HIV-1 Western blot. The positive predictive values were 99.6% for HIVCHEK plus SERODIA-HIV and 99.5% for HIVCHEK1+2 plus SERODIA-HIV; the negative predictive values were 97.8 and 97.9% respectively. Among 1495 pregnant women 90 were Western blot-positive for HIV-1 (6.0%) and 54 of 1510 blood donors were HIV-1 Western blot-positive (3.6%. None were positive for HIV-2. The sensitivities of HIVCHEK plus SERODIA-HIV and HIVCHEK1+2 plus SERODIA-HIV in these groups were 98.6% and 99.3% respectively and the specificities were 99.8 and 99.7%. The positive and predictive values of HIVCHEK plus SERODIA-HIV were 96.6 and 99.9% respectively and they were 94.1 and 99.9% respectively for HIVCHEK1+2 plus SERODIA-HIV. These instrument-free testing strategies are efficient alternatives for serodiagnosis of HIV-1 infection although their cost should be further reduced. (authors)