Combination of PURE-DNA extraction and LAMP-DNA amplification methods for accurate malaria diagnosis on dried blood spots

• Published in: Malaria Journal
• Main Authors: Jeanne Perpétue Vincent, Kanako Komaki-Yasuda, Moritoshi Iwagami, Satoru Kawai, Shigeyuki Kano
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2018
• Subjects: Malaria diagnosis; Procedure for ultra rapid extraction (PURE); Loop-mediated isothermal amplification (LAMP); Dried blood spots (DBS); Nested PCR; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-018-2527-7; https://doaj.org/article/c9f1920533dc4b4d80989ade8f094151

Abstract Background Malaria is one of the most important parasitic infectious diseases for which almost half of the world’s population is at risk. Although several diagnostic methods are now available to detect the infection, more sensitive and applicable tests are still required in the field. The loop-mediated isothermal amplification (LAMP) method is a DNA amplification tool in which the DNA amplification can be achieved by incubation at a stable temperature. A malaria detection kit based on this methodology has already been commercialized and is being used in some countries. The kit includes two reaction tubes: one targeting the common Plasmodium genus (Pan tube) and the other specifically targeting Plasmodium falciparum (Pf tube). In parallel, a simple DNA extraction method, the procedure for ultra rapid extraction (PURE), which can produce a DNA solution suitable for the LAMP reaction without the use of a centrifuge, has also become available. In this study, the sensitivity of the combination of the PURE and LAMP methods (PURE–LAMP) was evaluated with archived dried clinical blood samples of imported malaria cases, including P. falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Results Using a nested PCR as the reference, 117 samples including 46 P. falciparum, 7 P. vivax, 9 P. ovale, 4 P. malariae, and 51 negative cases were tested. The PURE–LAMP Pan correctly identified 64 of the 66 positives and the 51 negatives. Among the Pan-positive samples 45 P. falciparum were also detected with the PURE–LAMP Pf. The PURE–LAMP Pan and PURE–LAMP Pf had respective sensitivities of 96.96% (95% CI 89.47–99.63) and 97.82% (95% CI 88.47–99.94) and common specificity of 1. Conclusion The PURE–LAMP system is accurate when used with dried blood spots and extendable to the field.