Assessment of false negative rates of lactate dehydrogenase-based malaria rapid diagnostic tests for Plasmodium ovale detection

Currently, malaria rapid diagnostic tests (RDTs) are widely used for malaria diagnosis, but test performance and the factors that lead to failure of Plasmodium ovale detection are not well understood. In this study, three pLDH-based RDTs were evaluated using cases in China that originated in Africa. The sensitivity of Wondfo Pf/Pan, CareStart pLDH PAN and SD BIOLINE Pf/Pan in P. ovale detection was 70, 55 and 18%, respectively. CareStart was worse at detecting P. o. curtisi (36.5%) than at detecting P. o. wallikeri (75.0%), and SD could not detect P. o. curtisi. The overall detection ratio of all three RDTs decreased with parasite density and pLDH concentration. Wondfo, CareStart and SD detected only 75.0, 78.1 and 46.9% of the P. ovale cases, respectively, even when the parasitemia were higher than 5000 parasites/μL. Subspecies of P. ovale should be considered while to improve RDT quality for P. ovale diagnosis to achieve the goal of malaria elimination.