In vitro diagnosis of HIV: evaluation of the overall agreement of OnSite HIV 1/2 Ab plus Combo rapid test-cassette using reference samples in Cameroon

CaHReF 20116, Yaoundé Conges hall, 23 – 26 August 2016 , PL034

Department of Biomedical Sciences of the University of Dschang

In countries with limited resources, increase HIV testing is essential in working towards universal access to HIV prevention and treatment. Owing to the possibility of great variability of rapid tests over place and time, we hereby evaluated the overall agreement of OnSite HIV 1/2 Ab Plus Combo Rapid test-cassette using reference samples in Cameroon.

A transversal study performed at the virology laboratory of Centre Pasteur of Cameroon, constituted a reference panel of 100 samples. These samples were separated into two different groups; 50 HIV positives (5 HIV-2, 36 HIV-1 group-M, and 9 HIV-1 group-O) and 50 HIV negative samples. Each sample was further screened using OnSite HIV 1/2 Plus Combo Rapid Test and its characteristic performances were determined by estimating the sensitivity, specificity, the positive predictive value and the negative predictive value.
Among the positive panel, 44 out of the 50 were truly positive with OnSite HIV1/2 with a sensitivity of 88.0%. Meanwhile, 49 out of the 50 negatives were truly negative with OnSite, with a specificity of 98.0%. Also, an overall agreement (efficiency) of 93.0%, a negative predictive value of 89% and a positive predictive value of 97.8% were obtained with OnSite HIV1/2. Similarly, only 5 out of the 9 HIV-1 group O were detected as positive, 34 out of 36 HIV-1 group M were detected as positive, with a sensitivity of 55.6% and 94.4% respectively. The test was positive for all HIV-2 samples.

Conclusively, WHO recommends, ideally, a first-line assay with a sensitivity of 100% and a second-line assay with a specificity of 100%. Therefore, OnSite HIV 1/2 Plus Combo Rapid Test cannot be used neither as a first-line essay no as a second-line essay, so, cannot be included in the national algorithm of HIV diagnosis in Cameroon. 

HIV 1/2, Specificity, Sensitivity, Rapid test, Diagnosis.