Performance of hrp-2 Based Rapid Test and Microscopy in the Diagnosis of Plasmodium falciparum in Benue State, Nigeria

Microscopy and RDTs are the most frequently used diagnostic tools for malaria case detection and management in every malaria endemic community. Prompt and accurate diagnosis of plasmodium infections is important for malarial case containment. The requirement of expertise and difficulties in the identification of malarial parasites using microscopy has made RDTs popular as they are rapid and easy to perform with minimum expertise. Most RDTs for malaria case management in Nigeria target the histidine rich protein-2 antigen (PfHRP2) to detect Plasmodium falciparum. This study was therefore conducted between April and August, 2018 to evaluate the performance of HRP-2 based RDTs and microscopy in Benue State, Nigeria. Finger prick blood samples were collected from 510 volunteered participants. Giemsa stain thick films and pfhrp2 based RDTs kits were used to determine malaria parasites and plasmodium antigens in blood samples respectively. The occurrence of malaria by microscopy was higher (89%) compare to RDT (21%) (P>0.05). Female had the highest malaria infection (89.9% ) by microscopy while male had the highest ( 45.8% ) malaria infection by RDT, in all there was no significant difference in the infection rates (P>0.0%).There was no significant difference in the distribution of malaria across the different age groups for both microscopy and RDT (P>0.05). HRP2 based RDT failed to identify 78.6% cases of malaria identified by microscopy resulting to false negatives. Compared to microscopy, Ag Care Start TM PfHRP2 based RDT had a poor sensitivity (21.4%) and specificity (82.1%) which does not meet the WHO recommendation of the minimum of 95% sensitivity and 97% specificity for RDTs. HRP2 based RDT missed 78.6% of malaria cases detected by microscopy. The poor performance of HRP-2 based RDT (Care Start TM malaria PfHRP-2 Ag RDT) in this study area could be as a result of exposure of the kits to high temperatures (>30o) or deletion of hrp2 genes. There is need to investigate the role of malaria RDT storage conditions and HRP2 gene deletion with respect to malaria RDT performance in the study area.