Assessing the diagnostic accuracy of the SD-Ov16 rapid diagnostic test compared to the O-150 qPCR for the diagnosis of onchocerciasis in high- and low-endemic settings of Ghana

Accurate diagnostic tools are essential for onchocerciasis elimination programs. The SD-Bioline Ov-16 rapid diagnostic test (RDT) has been widely adopted for field surveillance, but its performance compared to molecular methods requires evaluation. This study assesses the concordance between the SD-Bioline Ov-16 RDT and quantitative polymerase chain reaction (qPCR) assay for diagnosing onchocerciasis in selected endemic communities in Ghana. A community-based cross-sectional study was conducted between September and November 2023 in seven communities across three districts in the Volta and Oti Regions of Ghana. Participants aged ≥ 5 years were recruited using convenience sampling. Dried blood spots were tested using the SD-Bioline Ov-16 RDT, and skin snips were analysed by qPCR targeting the O-150 repeat sequence from the same individuals. Concordance was assessed using kappa statistics, and diagnostic performance was estimated with qPCR as the reference standard for this assessment. Out of 1,705 participants recruited, 901 with complete paired samples were analysed. The overall prevalence was 27.5% (248/901) by Ov-16 RDT and 2.9% (26/901) by qPCR. Overall concordance between the Ov-16 RDT and qPCR as reference was 73.4% with a kappa score of 0.0759 ( p < 0.001), indicating poor agreement. The Ov-16 RDT showed 65.4% sensitivity (95% CI: 44.3–82.8%) and 73.6% specificity (95% CI: 70.5–76.6%) when compared to qPCR. The poor concordance between Ov-16 RDT and qPCR reflects the fundamental difference between antibody detection (exposure) and parasite DNA detection (active infection). While the Ov-16 RDT remains useful for surveillance, its limitations in detecting low-level infections necessitate improved diagnostic tools to support WHO’s 2030 elimination goals.