Performance of a Novel Plasmodium falciparum Rapid Diagnostic Test in Areas of Widespread hrp2/3 Gene Deletion.

BACKGROUND: Rapid diagnostic tests (RDTs) have improved malaria diagnosis; however, the emergence of hrp2/3 gene deletions threatens the reliability of HRP2-based RDTs. This study evaluated the diagnostic performance of a novel RDT detecting both HRP2 and PfLDH in a single test line.

METHOD: A cross-sectional study was conducted at two health centers in Ethiopia, recruiting 1004 study participants. Blood samples were tested using the novel and comparator RDTs, using microscopy and nested polymerase chain reaction (PCR) as the reference standards. Plasmodium falciparum hrp2 and hrp3 genotyping and HRP2 and P. falciparum lactate dehydrogenase (PfLDH) antigen quantification were also conducted.

RESULTS: In this study setting, characterized by 80% of P. falciparum infections showing hrp2 or hrp3 deletion, the novel RDT showed a sensitivity of 77.4% and a specificity of 96%, surpassing the HRP2-only comparators Bioline™ Malaria Ag Pf (55.9%) and Bioline™ Malaria Ag Pf/Pv (56.8%). Its performance was comparable to the three-line Bioline™ Malaria Ag Pf/Pf/Pv RDT, which detects HRP2, PfLDH, and PvLDH, at 77.7% sensitivity. Additionally, the novel RDT exhibited the ability to detect P. falciparum cases across a broader range of HRP2 and PfLDH antigen concentrations compared to the comparator RDTs.

CONCLUSIONS: The single-line, easy-to-interpret index malaria RDT outperforms conventional HRP2-only RDTs, making it a promising tool for enhancing malaria diagnosis in regions with high hrp2/3 deletion prevalence. Clinical Trial Registration.  The study is registered on ClinicalTrials.gov ID NCT05286359.