Evaluation of the dried blood spot filter paper technology and five testing strategies of HIV-1 and HIV-2 infections in West Africa

Simple robust approaches are needed to monitor the prevalence and incidence of HIV in Africa. The aim of this study was to evaluate the use of dried blood spot (DBS) as an alternative to serum or plasma for sentinel surveillance. Paired DBS and blood samples were obtained from 200 patients attending a genito-urinary medicine clinic in West Africa. The gold standard of diagnosis was based on the combination of 3 enzyme-linked immunosorbent assays (ELISA) using serum. The presence of HIV antibodies in eluates of dried blood spots was detected by ELISA, Gelatin Particle Assay (GPA) and Pepti-Lav 1-2 in 5 different testing strategies. All 200 eluates were tested individually, and in addition pools of 5 eluates each were tested. The sensitivity of the testing strategies ranged from 95.0% (83.1-99.4%) to 100% and the specificity from 97.5% (93.7-99.3%) to 100%. Testing in pools of 5 did not affect sensitivity. Dried blood spots were easy to work with. Test kit and laboratory consumable costs varied between £492 and £1037 (unpooled strategies) and £163 and £421 (pooled). The monospecific ELISAs used in this study are no longer in production; currently available differentiating assays need to be tested. DBS are recommended for sentinel surveillance in Africa.