Evaluation of rapid PfHRP-2/pLDH-based tests in diagnosing microscopy-confirmed falciparum malaria in Hodeidah governorate, Yemen

Abstract

Along with the determination of malaria infection rate among suspected patients attending hospitals in Hodeidah governorate, the present study evaluated the accuracy of Plasmodium falciparum histidine-rich protein-2 (PfHRP-2)/parasite-specific lactate dehydrogenase (pLDH)-based rapid diagnostic test (RDT) for the diagnosis of microscopy-confirmed falciparum malaria. An overall malaria infection rate of 19.3% (57/295) among suspected patients attending hospitals was microscopically confirmed. The sensitivity of thin blood films for the detection of malaria parasites was 79.0% compared to thick films and was greatly affected by the parasite density, being 65.0% or less at parasite densities of ≤1000 parasites/μl of blood. Compared to light microscopy, the present study revealed sensitivity levels of 100.0% (95% CI: 92.0–100.0) vs. 94.7% (95% CI: 84.2–98.6), specificity levels of 97.3% (95% CI: 89.8–99.5) vs. 100.0% (95% CI: 93.9–100.0), positive predictive values of 89.9% (95% CI: 88.3–99.0) vs. 100.0 (95% CI: 91.6–100.0) and negative predictive values of 100.0% (95% CI: 93.9–100.0) vs. 98.7% (95% CI: 89.3–98.7) for the PfHRP-2 and pLDH components of SD BIOLINE® RDT, respectively, for falciparum malaria diagnosis. Therefore, the overall accuracy levels of the PfHRP-2 and pLDH components of the investigated RDT for the diagnosis of microscopy-confirmed falciparum malaria are 98.5% (95% CI: 94.6–99.6) and 97.7% (95% CI: 93.5–99.2), respectively.