Loop-mediated isothermal amplification (LAMP) assay for the diagnosis of imported malaria: a narrative review

Loop-mediated isothermal amplification (LAMP) is a molecular method to detect malaria recently introduced in the market. LAMP is simple to perform and does not require advanced equipment and training thus satisfying the qualification as a point-of-care diagnostic screening test. In this narrative review, we focus on the role of LAMP for malaria diagnosis in non-endemic settings. We searched PubMed, Embase, Scopus, and Google Scholar, using the following search terms: 'Malaria LAMP' in combination with 'imported malaria' or 'travellers' malaria' or 'non-endemic setting' or 'non-endemic region' or 'malaria screening' or 'malaria diagnosis'. References of each article were also reviewed for possible studies or reports not identified in our search. Overall, 18 studies encompassing 6289 tested samples with 1663 confirmed malaria diagnoses were retrieved. Most of these studies (13/18, 72.2%) were conducted in Europe, and almost half were retrospective. Fourteen studies (77.8%) employed real-time or nested-polymerase chain reaction as the reference method for confirming malaria diagnosis. Sensitivity of LAMP ranged from 93.9 to 100% and specificity from 93.8 to 100% with a negative predictive value of 99.6%-100%. The rate of reported invalid results requiring repeat of the test varied from 0.01% to 5.7%, but they were solved in the majority of cases with a secondary analysis. In non-endemic countries the adoption of LAMP malaria assay as the screening test for malaria diagnosis seems to perform better than conventional methods. However, blood microscopy remains essential to either identify Plasmodium species and quantify parasitaemia and adequately managing malaria cases.