Performance and Comparison of two Malaria Rapid Diagnostic Tests among Symptomatic Patients in Lagos, Southwest Nigeria

Abstract

Malaria remains a public health problem in Sub Saharan Africa. Microscopic identification of Plasmodium spp. is the gold standard for malaria diagnosis. However, malaria rapid diagnostic test kits are also available for prompt diagnosis, effective treatment and are important in reducing morbidity and mortality associated with malaria especially among high-risk groups. The use of malaria rapid diagnostic tests (RDTs) has improved Plasmodium falciparum diagnosis, especially in settings where quality microscopy is not available. Field evaluation of RDTs would assist in confirming the potency, performance of the RDTs and in ruling out or confirming malaria parasite. In this study, the performance of two RDTs were assessed for malaria diagnosis, using thick and thin blood smears as the gold standard. A total of 1,271 patients suspected to have malaria who gave consent were enrolled in the study within six months at St Matthew”s Primary Health Center Amukoko in Ajeromi Ifelodun LGA of Lagos state. The study population age range between 2-67years. This is a cross-sectional study involving patients with history of malaria symptoms. The SD Bioline and First Response HRP2 based MRDTs were evaluated in this study. Of the patients 1,271 screened for malaria, 185 were slide positive for malaria parasites. Blood smears and HRP2 First response RDT showed malaria prevalence rate of 14.6%, while the HRP2 SD Bioline RDT showed prevalence rate of 15.5%. The SD Bioline HRP2 RDTs showed a sensitivity of 61.1%, specificity of 92.3%, PPV of 57.4% and NPV of 93.3%, while the First response RDT showed a sensitivity of 58.9%, specificity of 93.1%, PPV of 59.6% and NPV of 92.9%. In this study, the sensitivity of the RDT increased with parasite density (>1000p/µl showed sensitivity >90%). All the malaria rapid diagnostic test kits performed relatively well and can be used in emergencies. Concerning cost-effectiveness, using the malaria RDTs at the hospital is cheaper than light microscopy for diagnosing malaria. However, for malaria diagnosis, malaria RDT kits cannot be relied upon alone; hence, microscopic confirmation is always required.