Diagnostic performance of rapid diagnostic tests for the diagnosis of malaria at public health facilities in north‐west Ethiopia

Abstract

Abstractobjective To assess the performance of RDTs against nested polymerase chain reaction (nPCR) for the diagnosis of malaria in public health facilities in north-western Ethiopia.methods Cross-sectional study at public health facilities in North Gondar, Ethiopia, of 359 febrile patients with signs and symptoms consistent with malaria. Finger prick blood samples were collected for testing in a P. falciparum/pan-malaria RDTs and for molecular analysis. Sensitivity, specificity and predictive values were determined for the RDTs using nPCR as reference diagnostic method. Kappa value was determined to demonstrate the consistency of the results between the diagnostic tools.results By RDTs, 22.28% (80/359) of patients tested positive for malaria, and by nPCR, 27.02% (97/359) did. In nPCR, 1.67% (6/359) and 0.28% (1/359) samples were positive for P. ovale and P. malariae, which had almost all tested negative in the RDTs. The sensitivity, specificity, positive and negative predictive values of RDTs for the diagnosis of malaria were 62.9%, 92.7%, 76.3% and 87.1%, respectively, with 0.589 measurement agreement between RDTs and nPCR. The sensitivity and specificity of RDTs for P. falciparum identification only were 70.8% and 95.2%, and 65.2% and 93.1% for P. vivax.conclusion Although RDTs are commonly used at health posts in resource-limited environments, their sensitivity and specificity for the detection and species identification of Plasmodium parasites were poor compared to nPCR, suggesting caution in interpreting RDTs results. Particularly, in the light of expanded efforts to eliminate malaria in the country, more sensitive diagnostic procedures will be needed.

Can malaria rapid diagnostic tests by drug sellers under field conditions classify children 5 years old or less with or without Plasmodium falciparum malaria? Comparison with nested PCR analysis

“…In the current study, the observed sensitivity of the laboratory scientist strategy is higher than estimates from similar studies [ 56 , 57 ]. An evaluation of Pf -HRP2 RDT (CareStart™) using samples from suspected malaria cases aged 1–81 years using PCR as the reference, reports sensitivities ranging from 71% [ 56 ], 72% to 75% [ 57 ] as compared to 87% in the current study. The difference in findings could be explained by the inclusion of study participants of all ages yet the current study analysed samples taken from children 5 years old or less.…”

“…On the contrary, an evaluation of Pf -HRP2 malaria RDTs (MAKROmed™) against PCR as reference among 853 women in Burkina Faso reports almost similar sensitivity of 90% [ 58 ] as the current study. The specificity of the laboratory scientist re-reading of the RDT strips against PCR as reference in the current study is the same as observed in north-west Ethiopia (95%) [ 56 ], but higher than estimates from western Kenya (82%) [ 57 ] and Burkina Faso (65%) [ 58 ].…”

“…The variability in sensitivity and specificity of Pf -HRP2 RDTs as observed in the current study and other studies [ 56 – 59 ] warrants a larger scale examination of the magnitude of the misclassification with current RDTs. Moreover, these field estimates are below the minimum WHO thresholds for sensitivity and specificity of 95 and 90% for all malaria species, respectively [ 60 ].…”

“…The difference in findings could be explained by the inclusion of study participants of all ages yet the current study analysed samples taken from children 5 years old or less. Getnet et al reports that sensitivity of RDTs when compared to PCR as reference is higher in study population under 18 years than older ages [ 56 ]. On the contrary, an evaluation of Pf -HRP2 malaria RDTs (MAKROmed™) against PCR as reference among 853 women in Burkina Faso reports almost similar sensitivity of 90% [ 58 ] as the current study.…”

Performance of loop-mediated isothermal amplification (LAMP) for the diagnosis of malaria among malaria suspected pregnant women in Northwest Ethiopia

“…Polymerase chain reaction (PCR) in its various formats has emerged as the most sensitive method able to detect low levels of parasites in the blood especially in this setting [36, 37]. However, PCR requires high capital investment costs, service agreements, reagent supplies, and trained staff in molecular technologies with robust quality assurance programmes.…”