Laboratory diagnosis of malaria: Comparing giemsa stained thick blood films with rapid diagnostic test (RDT) in an endemic setting in North-west Nigeria

Abstract

Malaria microscopy will continue to remain the gold standard for the diagnosis of malaria, but prolonged turnaround time and lack of malaria microscopist that are associated with this technique continue to impact on the quality of service rendered by the laboratory, especially the turnaround time, which is one of the quality indicators to measure laboratory quality systems. The prolonged turnaround time and lack of malaria microscopists identified with resource constraint setting in the midst of a period with high transmission of malaria prompted us to search for an alternative to the gold standard. Hence, multi-species were evaluated based on the rapid diagnostic test to determine its importance in the laboratory diagnosis of malaria. The rapid diagnostic test kit (SD Bioline – FK80) used in this study is based on the detection of Plasmodium falciparum, histidine rich protein-2 (HRP-2) and Plasmodium vivax-specific lactose dehydrogenase (Pv-pLDH), and was compared against traditional malaria microscopy. The evaluation was designed to provide data on the use of rapid diagnostic test and microscopy for malaria diagnosis in an urban secondary health facility with laboratory component. In total, 939 patients that consulted the out-patient department were clinically evaluated and suspected for malaria. Blood samples of those patients were subsequently tested using both techniques. The sensitivity and specificity for P. falciparum were 75.2 and 80.4%, respectively. The accuracy of the test was 76.8%. It was concluded that the rapid diagnostic test could be used as the first screening test for malaria diagnosis and have to be confirmed by microscopy if the outcome is negative. This will therefore improve on the current situation of treating patients for malaria without laboratory outcome to confirm clinical evaluation.\t\tKey words: Rapid diagnostic kit, malaria, Nigeria, microscopy, sensitivity, specificity.\t