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

Abstract

Background: 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 and not conclusive.

Methods: Paired clinical samples of venous and capillary blood from 141 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: No significant differences in Plasmodium parasite detection between capillary and venous blood for both assays were observed. The GFP assay was more sensitive than MMSR for all markers that could be compared (Plasmodium spp. and Plasmodium falciparum) in both venous and capillary blood.

Conclusions: No difference was found in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data gives support for use of capillary blood, a material which can be obtained easier by less invasive methods, for PCR-based malaria diagnostics, independent of the platform.

Keywords: Capillary blood; Malaria; Multiplex polymerase chain reaction; Plasmodium; Plasmodium falciparum; Plasmodium ovale; Plasmodium vivax; Sierra Leone; Venous blood.

Fig. 1

Comparison of Ct values obtained with venous (abscissa) and capillary (ordinate) samples positive for malaria markers after analysis using GFP. Panels A and B show Ct values for samples positive for Plasmodium spp. (a) and P. falciparum (b). Gray circles at the edges of each graph represent samples that were positive in venous but not matched capillary samples (above the main plot) or in capillary but not matched venous samples (to the right of each plot)

Fig. 2

Comparison of Ct values obtained with venous (abscissa) and capillary (ordinate) samples positive for malaria markers after analysis using MMSR. Panels A and B show Ct values for samples positive for Plasmodium spp. (a) and P. falciparum (b). Gray circles at the edges of each graph represent samples that were positive in venous but not matched capillary samples (above the main plot) or in capillary but not matched venous samples (to the right of each plot)