Comparison of capillary and venous blood for malaria detection using two PCR-based assays in febrile patients in Sierra Leone

Abstract

Background Malaria parasites infect over 200 million people and cause more than 400,000 deaths each year. Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials the published data on this subject are scarce are not conclusive. Methods Paired samples of venous and capillary blood from 103 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay. Results We observed no significant differences in Plasmodium parasite detection between capillary and venous blood when using the MMSR assay. In GFP assays, however, markers for Plasmodium spp. and P. falciparum were detected at significantly higher numbers of venous samples (p<0.002 and p<0.05, respectively). The GFP assay was more sensitive than MMSR for Plasmodium spp. in both types of samples and overall more sensitive (taking all detected malaria markers into account) in venous samples only. Conclusions Malaria detection sensitivity may be higher for venous blood compared to capillary blood in case of certain targets when using PCR-based detection methods. The overall sensitivity of GFP assay was generally higher than MMSR but depended on the target and clinical material used.