Field evaluation of the novel One Step Malaria Pf and Pf/Pv rapid diagnostic tests and the proportion of HRP-2 gene deletion identified on samples collected in the Pwani region, Tanzania

BACKGROUND: Malaria rapid diagnostic tests (mRDTs) have played an important role in the early detection of clinical malaria in an endemic area. While several mRDTs are currently on the market, the availability of mRDTs with high sensitivity and specificity will merit the fight against malaria. We evaluated the field performance of a novel One Step Malaria (P.f/P.v) Tri-line and One Step Malaria (P.f) rapid test kits in Pwani, Tanzania. METHODS: In a cross-sectional study conducted in Bagamoyo and Kibiti districts in Tanzania, symptomatic patients were tested using the SD BIOLINE, One Step Malaria (P.f/P.v) Tri-line and One Step Malaria (P.f) rapid test kits, microscope, and quantitative Polymerase Chain Reaction (qPCR). An additional qPCR assay was carried out to detect Histidine-Rich Protein 2 (HRP-2) gene deletion on mRDT negative but microscope and qPCR positive samples. Microscope results confirmed by qPCR were used for analysis, where qPCR was used as a reference method. RESULTS: The sensitivity and specificity of One Step P.f/P.v Tri-line mRDTs were 96.0% (CI 93.5–97.7%) and 98.3% (CI 96.8–99.2%), respectively. One Step P.f mRDT had sensitivity and specificity of 95.2% (CI 92.5–97.1%) and 97.9% (CI 96.3–99.0%) respectively. Positive predictive value (PPV) was 97.6% (CI 95.4–98.7%) and negative predictive value (NPV) was 96.2% (CI 95.5–98.3%) for the One Step P.f/P.v Tri-line mRDTs respectively, while One Step P.f mRDT had positive predictive value (PPV) and negative predictive value (NPV) of 97.0% (CI 94.8–98.3%) and 96.7 (CI 94.9–97.9%) respectively. 9.8% (CI 7.84–11.76) of all samples tested and reported to be malaria-negative by mRDT had HRP-2 gene deletion. CONCLUSION: One Step Malaria P.f/P.v Tri-line and One Step Malaria P.f rapid test kits have similar sensitivity and specificity as the standard mRDT that is currently in the market, demonstrating the potential to contribute in the fight against malaria in endemic settings. However, the identified malaria parasites population with HRP-2 gene deletion pose a threat to the current mRDT usability in the field and warrants further investigations.