Field performance of Plasmodium falciparum lactate dehydrogenase rapid diagnostic tests during a large histidine-rich protein 2 deletion survey in Ethiopia

• Published in: Malaria Journal
• Main Authors: Sindew Mekasha Feleke, Bokretsion Gidey, Hussein Mohammed, Desalegn Nega, Dereje Dillu, Mebrhatom Haile, Hiwot Solomon, Jonathan B. Parr, Getachew Tollera, Geremew Tasew, Hassen Mamo, Beyene Petros
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Malaria; PLDH; Diagnostics; Elimination; Ethiopia; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04257-9; https://doaj.org/article/0e0e3bc4b1c64ef0be30b4e7772a2b7e

Abstract Background Malaria rapid diagnostic tests (RDTs) have expanded diagnostic service to remote endemic communities in Ethiopia, where 70% of malaria services per annum are reliant on them. However, diagnostic strategies are threatened by Plasmodium falciparum parasites with deletions of the histidine-rich protein 2 and/or 3 (pfhrp2/3) genes. Studies have reported pfhrp2/3 gene deletion prevalence in Ethiopia that exceeds the WHO recommended threshold to switch to non-HRP2 targeted RDTs for detection of P. falciparum. Therefore, RDTs that target alternative antigens, such as P. falcipar um lactate dehydrogenase (PfLDH) are increasingly in programmatic use. Methods Malaria suspected patients visiting health facilities of Amhara, Tigray, Gambella, and Oromia regions of Ethiopia were screened by community health workers using Carestart Pf/Pv (HRP2/Pv-LDH) and SD-Bioline Pf (HRP2 for Pf/LDH for Pf) RDTs. Dried blood spot (DBS) samples were collected from selected patients for molecular and serological analysis. The clinical data and RDT results were recorded on standard forms, entered into EpiInfo, and analysed using STATA. The Pf-LDH detecting RDT results were compared with real-time PCR and bead-based immunoassay to determine their diagnostic performance. Results The 13,172 (56% male and 44% female, median age of 19 years ranging from 1 to 99 year) study participants were enrolled and tested with PfHRP2 and PfLDH detection RDTs; 20.6% (95% CI: 19.6 to 21.6) were P. falciparum RDT positive. A subset of samples (n = 820) were previously tested using P. falciparum lactate dehydrogenase (pfldh) quantitative real-time PCR, and 456 of these further characterized using bead-based immunoassay. The proportion of samples positive for P. falciparum by the PfHRP2 Carestart and SD-Bioline RDTs were 66% (539/820) and 59% (481/820), respectively; 68% (561/820) were positive for the PfLDH band on the SD-Bioline RDT. The sensitivity and specificity of the PfLDH RDT band were 69% and 38%, respectively, versus pfldh qPCR; and ...