Evaluating 18s-rRNA LAMP and selective whole genome amplification (sWGA) assay in detecting asymptomatic Plasmodium falciparum infections in blood donors

• Published in: Malaria Journal
• Main Authors: Enoch Aninagyei, Stella Smith-Graham, Alex Boye, Alexander Egyir-Yawson, Desmond Omane Acheampong
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2019
• Subjects: 18s-rRNA-LAMP; Crude DNA LAMP; Purified DNA LAMP; Selective whole genome amplification; P. falciparum histidine rich protein 2; Plasmodium lactate dehydrogenase; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-019-2850-7; https://doaj.org/article/40325139fd0948fd9146b79fb9c44c97

Abstract Background Undesirable consequences of donor Plasmodium falciparum parasitaemia on stored donor blood have been reported. Therefore, it is imperative that all prospective blood donors are screened for P. falciparum infections using sensitive techniques. In this study, the sensitivities of microscopy, rapid diagnostic test (RDT), loop-mediated isothermal amplification (LAMP) assay and selective whole genome amplification (sWGA) technique in detecting P. falciparum infections in blood donors was assessed. Methods Randomly selected blood donors from 5 districts in Greater Accra Region of Ghana were screened for asymptomatic P. falciparum infections. Each donor sample was screened with SD Bioline RDT kit for P. falciparum histidine rich protein 2 and Plasmodium lactate dehydrogenase antigens, sWGA and 18s-rRNA LAMP. Crude DNA LAMP (crDNA-LAMP) was compared to purified DNA LAMP (pDNA-LAMP). Results A total of 771 blood donors were screened. The respective overall prevalence of P. falciparum in Ghana by microscopy, RDT, crDNA-LAMP, pDNA-LAMP and sWGA was 7.4%, 11.8%, 16.9%, 17.5% and 18.0%. Using sWGA as the reference test, the sensitivities of microscopy, RDT, crDNA-LAMP and pDNA-LAMP were 41.0% (95% CI 32.7–49.7), 65.5% (95% CI 56.9–73.3), 82.6% (95% CI 75.8–88.3) and 95.7% (95% CI 90.1–98.4), respectively. There was near perfect agreement between LAMP and sWGA (sWGA vs. crDNA-LAMP, κ = 0.87; sWGA vs. pDNA-LAMP, κ = 0.96), while crDNA-LAMP and pDNA-LAMP agreed perfectly (κ = 0.91). Goodness of fit test indicated non-significant difference between the performance of LAMP and sWGA (crDNA-LAMP vs. sWGA: x 2 = 0.71, p = 0.399 and pDNA-LAMP vs. sWGA: x 2 = 0.14, p = 0.707). Finally, compared to sWGA, the performance of LAMP did not differ in detecting sub-microscopic parasitaemia (sWGA vs. crDNA-LAMP: x 2 = 1.12, p = 0.290 and sWGA vs. pDNA-LAMP: x 2 = 0.22, p = 0.638). Conclusions LAMP assay agreed near perfectly with sWGA with non-significant differences in their ability to detect asymptomatic P. falciparum ...