Diagnostic performance of ultrasensitive rapid diagnostic test for the detection of Plasmodium falciparum infections in asymptomatic individuals in Kisangani, Northeast Democratic Republic of Congo

BACKGROUND: Ultrasensitive rapid diagnostic test (usRDT) was recently developed to improve the detection of low-density Plasmodium falciparum infections. However, its diagnostic performance has not been evaluated in the Democratic Republic of Congo (DRC). This study aims to determine the performance of the usRDT in malaria diagnosis in asymptomatic individuals under field condition in Kisangani, Northeast of DRC. METHODS: A community-based cross-sectional study was carried out from June to August 2022 on 312 asymptomatic individuals residing in the city of Kisangani. Capillary blood samples were collected by finger prick for microscopic examination of thick and thin blood film, RDTs, and nested polymerase chain reaction (PCR). Alere™ Malaria Ag P.f usRDT and conventional RDT (cRDT/SD Bioline Malaria Ag P.f) kits were used for the detection of Plasmodium histidine rich protein 2 (HRP2) antigen as a proxy for the presence of P. falciparum. The diagnostic performance of the usRDT was compared with cRDT, microscopy and PCR. RESULTS: The prevalence of asymptomatic P. falciparum malaria was 40.4%, 42.0%, 47.1% and 54.2% by cRDT, microscopy, usRDT and PCR, respectively. By using PCR as a reference, usRDT had sensitivity and specificity of 87.0% (95% CI 81.4-91.7) and 100.0% (95% CI 97.5-100.0), respectively, whereas the cRDT had sensitivity and specificity of 74.6% (95% CI 67.3-80.9) and 100% (95% CI 97.1-100.0), respectively. By using microscopy as a reference, usRDT had sensitivity and specificity of 96.9% (95% CI 92.4-99.2) and 89.0% (95% CI 83.5-93.1), respectively, while the cRDT had sensitivity and specificity of 96.2% (95% CI 92.3-98.7) and 100% (95% CI 97.9-100.0), respectively. CONCLUSION: The usRDT showed better diagnostic performance with higher sensitivity than the cRDT which is currently in use as point-of-care test. Further research is necessary to assess the access and cost-effectiveness of the usRDTs to use for malaria surveillance.