Evaluation of four simple/rapid assays and two fourth-generation ELISAs for the identification of HIV infection on a serum panel representing the HIV-1 group M genetic diversity in Cameroon

The performance of 4 rapid and simple assays: Camstix-HIV 1+2 (Camdiagnostix, Yaounde, Cameroon); Determine HIV 1+2+0 (Abbott Laboratories, Tokyo, Japan); Genie II HIV-1/HIV-2 (Bio-Rad, Marnes la Coquette, France); ImmunoComb II HIV 1 & 2 BiSpot (Orgenics, Yavne, Israel); and 2 fourth-generation ELISAs: Enzygnost HIV Integral (Dade Behring, Marburg, Germany) and Genscreen plus HIV Ag-Ab (Bio-Rad, Marries la Coquette, France) currently used in Cameroon to detect HIV infections were evaluated on a local serum panel. A total of 503 samples were collected, using the Camstix-HIV 1+2 assay. Overall, 280 samples were confirmed HIV positive, 181 were negative, and 42 were indeterminate. All positive samples belonged to group M: CRF02_AG (73.5%), A1 (7.1%), A2 (1.2%), G (4.7%), F2 (5.1%), D (1.6%), CRF11 (1.6%), CRF06 (1.2%), and CRF01_AE (1.6%). Sensitivity, specificity, test efficiency, and positive and negative predictive values were calculated both including and excluding indeterminate samples. Except for Genie II and ImmunoComb II (98.9 and 99.3%, respectively), sensitivities were 100% for the remaining 4 tests. Specificities, efficiencies, and positive predictive values of all assays were negatively affected by the addition of HIV-indeterminate samples in the calculations. These data show the importance of prior test evaluations on local serum panels and in field conditions before a national policy for HIV screening is decided on and stress also the need to use tests and algorithms that can reduce the high number of HlV-indeterminate results in Africa.