Field evaluation of a novel one step malaria p.f and p.f/p.v rapid diagnostic tests in Pwani region, Tanzania

Abstract

Malaria rapid diagnostic tests (mRDTs) play an important role in the early detection of symptomatic and asymptomatic malaria in endemic areas. While several mRDTs are currently on the market, the availability of mRDTs with high sensitivity and specificity will add value in the fight against malaria. We evaluated the field performance for malarial diagnosis of a novel One Step Malaria (P.f/P.v) Tri-line and One Step Malaria (P.f) rapid test kits in Pwani, Tanzania. 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 qPCR. Samples tested positive by microscope, and verified by qPCR as the confirmatory method were analysed to determine sensitivity of the test kits. An additional qPCR assay was carried out to detect HRP-2 gene deletion on mRDT negative but microscope and qPCR positive samples. The sensitivity and specificity of One-step P.f/P.v Tri line mRDTs was 96.0% (CI: 93.5% to 97.7%) and 98.3% (CI: 96.8% to 99.2%) respectively. One step P.f mRDT had sensitivity and specificity of 95.2% (CI: 92.5% to 97.1%) and 97.9% (CI: 96.3% to 99.0%), respectively. Positive predictive value (PPV) was 97.6 % (CI:95.4% to 98.7%) and negative predictive value (NPV) was 96.2% (CI:95.5% to 98.3%) for the One-step P.f/P.v Tri line mRDTs., while One step P.f mRDT had positive predictive value (PPV) and negative predictive value (NPV) of 97.0% (CI:94.8% to 98.3% ) and 96.7(CI:94.9% to 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. 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 areas. However, the identified malaria parasites population with HRP-2 gene deletion pose threat to the current mRDT usefulness in the field and warrants further investigations.