Using dried blood spot for the detection of HBsAg and anti-HCV antibodies in Cameroon.

OBJECTIVE: Dried blood spots (DBS) offer multiple benefits for collecting, storing and shipping whole blood samples. Our objective was to compare, for the first time in Africa, the performance of DBS with respect to plasma in the detection of Hepatitis B surface antigen (HBsAg) and antibodies to Hepatitis C Virus (anti-HCV) using Architect, Abbott Diagnostics. RESULTS: DBS had a sensitivity of 99%, a specificity of 100%, a positive predictive value of 99%, a negative predictive value of 100% and a kappa index of 0.99 for the detection of HBsAg. For anti-HCV detection, the sensitivity, specificity, positive predictive value, negative predictive value and kappa index were 99%, 98%, 98%, 99%, and 0.97, respectively. This study confirms that DBS may be a reliable alternative specimen type for HBV and HCV diagnosis.

Evaluation of the performances of twelve rapid diagnostic tests for diagnosis of HIV infection in Yaounde, Cameroon.

According to the WHO/UNAIDS recommendations, an acceptable HIV rapid diagnostic tests (RDTs) has to perform a sensitivity≥99% and a specificity≥98%. Given the constant release of new RDTs for HIV testing in the market and the high HIV genetic diversity in Cameroon, it is interesting to monitor their performances in that setting. A total of 240 HIV positive (including 219 HIV-1 M, 15 HIV-1 O, 1 HIV-1 N, 1 HIV-1 M/O recombinant and 4 HIV-2) and 240 HIV negative plasma samples were used to evaluate twelve routinely used RDTs in Cameroon. A reference algorithm combining Enzyme Immunoassays and nucleic acid testing was used as gold standard. The sensitivity, specificity, positive predictive value, and negative predictive value of the twelve RDTs evaluated varied between 93.7 and 100%; 95.8 and 100%; 96.0 and 100%, and 94.1 and 100%, respectively. Five out of the twelve RDTs could not detect some HIV-1 O variants, one of them failed to detect an HIV-2 variant while all them efficiently detected HIV-1 N and HIV M/O recombinant. Our findings underscore the need to monitor the performances of RDTs to be used for HIV testing in Cameroon using locally obtained well-characterized samples panels.