Geneva Health Forum 2024

Evaluation Biocredit RDTs for Detection Plasmodium Species, HRP2/3 Gene Deletions by highly sensitive digital PCR

Not scheduled

15m

Geneva

Oral presentation or scientific poster Towards the elimination of malaria

Description

Alayu Bogale1,2, Fitsum Girma 2, Migbaru Keffale 2Teferi Eshetu 3 Teshome Degefa 3
Dilla University1, Department of Medical Laboratory Science, College of Medicine and Health Sciences, Dilla, Ethiopia. *= Corresponding author, Email= bgialex11@gmail.com, Cell phone: 0936680141. Armauer Hansen Research Institute (AHRI)2, FMoH, Ethiopia, Jimma University3.
ABSTRACT
Background: Rapid diagnostic test (RDT) plays an essential role for prompt diagnosis of malaria in settings where using microscopy is not feasible. However, there is an increasing concern that Plasmodium falciparum histidine rich protein (PfHRP) gene deletions could impede the performance of the commonly used RDTs, resulting in a false negative diagnosis. This suggests the need to develop and evaluate new RDT kits to overcome such challenges.
Methods: A health facility-based cross-sectional study was conducted from September to December 2022 in 384 malaria suspected febrile study subjects at Maksegnt Health Center. Finger-prick blood samples were collected for malaria diagnosis using microscopy, RDTs and qPCR. Sensitivity, specificity, predictive values of the RDTs were determined by comparing with the gold standard microscopy and qPCR Digital Polymerase Chain Reaction (dPCR) was used to detect PfHRP 2/3 gene deletion.
Results: By taking microscopy as a reference, the Biocredit Pf/Pv (pLDH/pLDH) RDT had sensitivity and specificity of 97.9% and 97.4% for P. falciparum and 94.5% and 97.5% for P. vivax, respectively. The Biocredit Pf (pLDH/HRP2) RDT had sensitivity and specificity of 97.4% and 97.5%. In contrast, SD Bioline RDT had sensitivity and specificity of 51.3% and 93.2% for P. falciparum, and 86.3% and 96.5% for P. vivax, respectively. Out of 99 SD Bioline RDT negative samples, Pfhrp2 and Pfhrp3 exon 2 gene deletions were observed in 23.2% and 27.7% of the PCR-positive samples, respectively. Double deletions in pfhrp2 and pfhrp3 were detected in 13.1% (26/198) of the PCR positive samples.
Conclusion: The sensitivity and specificity of Biochredit RDTs kits documented in this study comply with the WHO limit of detection, with more reliable diagnostic performance compared to the conventional (SD Bioline) RDT. This study confirms the presence of 13.1% of pfhrp2/3 gene deletions So, we should consider alternative diagnostic tool like Pf-pLDH in the study area.
Keywords: Plasmodium falciparum, Plasmodium vivax, RDTs, hrp 2/3, Ethiopia