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 crDNALAMP
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: x2 = 0.71, p = 0.399 and pDNA-LAMP vs. sWGA: x2 = 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: x2 = 1.12, p = 0.290 and sWGA vs. pDNA-LAMP: x2 = 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 parasitaemia in blood donors. Therefore, it is recommended that LAMP based assays are
employed to detect P. falciparum infections in blood donors due to its high sensitivity, simplicity, cost-effectiveness
and user-friendliness.
