Evaluation of the Clinical Performance of Two New Onchocerciasis Rapid Diagnostic Tests

Current diagnostic methods for onchocerciasis lack sufficient utility, sensitivity or specificity. Two new lateral flow assays developed by Bioaster and Global Access Diagnostics (BA/GADx) and Drugs and Diagnostics for Tropical Diseases (DDTD) multi-antigen test Biplex Version C (DDTDc) were evaluated in Ghanaian communities to assess their potential for point-of-care use. The study enrolled 1,700 participants (≥5 years) across seven communities. The tests were evaluated on whole blood in the field and dried blood spots (DBS) in the laboratory. The results were compared with the existing SD Ov16 RDT test of DBS and O-150 qPCR on skin snips. Cross-reactivity was assessed via Mansonella perstans qPCR. The sensitivities of the DDTDc compared to the SD Ov16 ranged from 75.52% - 85.57%, while that of the BA/GADx ranged from 83.33% - 88.74%. The confidence intervals for the sensitivity of these two tests overlap. Tests on the DBS yielded the highest sensitivity for both tests. Skin snip qPCR identified only 26 positives, limiting specificity assessments. Both tests demonstrated field usability and adequate sensitivity compared to the SD Ov16 RDT. These advancements represent progress toward diagnostic tools available for elimination programs but underscore the need for continued diagnostic innovation to address the lingering challenges.