Clinical COVID-19 diagnostic methods: Comparison of reverse transcription loop-mediated isothermal amplification (RT-LAMP) and quantitative RT-PCR (qRT-PCR)

• Published in: Journal of clinical virology Vol. 139; p. 104813
• Main Authors: Kitajima, Heita, Tamura, Yoshitaka, Yoshida, Hiroko, Kinoshita, Hitomi, Katsuta, Hiroki, Matsui, Chika, Matsushita, Akane, Arai, Tsuyoshi, Hashimoto, Shoji, Iuchi, Atsuhiko, Hirashima, Tomonori, Morishita, Hiroshi, Matsuoka, Hiroto, Tanaka, Toshio, Nagai, Takayuki
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2021
• Subjects: COVID-19; COVID-19 - diagnosis; COVID-19 - virology; COVID-19 Nucleic Acid Testing - methods; Diagnosis; Humans; Molecular Diagnostic Techniques - methods; Nucleic Acid Amplification Techniques - methods; Polymerase chain reaction; RT-LAMP; SARS-CoV-2; SARS-CoV-2 - genetics; Sensitivity and Specificity; Sputum; Viral Load; COVID-19; RT-LAMP; Polymerase chain reaction; SARS-CoV-2; NIID; RT-PCR; Sputum; Diagnosis
• DOI: 10.1016/j.jcv.2021.104813
• ISSN: 1386-6532; 1873-5967

•RT-LAMP requires less time, skill, and equipment than qRT-PCR.•Using nasopharyngeal and sputum samples, the methods provided similar accuracy.•RT-LAMP showed similar performance for samples with cycle threshold value below 36.•RT-LAMP should be considered as a diagnostic tool for more diverse settings. The coronavirus disease 2019 (COVID-19) pandemic is a major public health concern. Accurate and rapid diagnosis of COVID-19 is critical for disease control. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a nucleic acid amplification assay similar to reverse transcription-polymerase chain reaction (RT-PCR), the former being a simple, low cost, and rapid method. This study aimed to compare the RT-LAMP assay with RT-PCR using the Loopamp™ SARS-CoV-2 Detection Kit. One hundred and fifty-one nasopharyngeal swab and 88 sputum samples obtained from individuals with suspected or confirmed COVID-19 were examined. RT-LAMP had high specificity (98.5 % (95 % CI: 96.9–100 %)), sensitivity (87.0 % (95 % CI: 82.8–91.3 %)), positive predictive value (97.9 % (95 % CI: 96.1–99.7 %)), negative predictive value (90.2 % (95 % CI: 86.4–94.0 %)), and concordance rate (93.3 % (95 % CI: 90.1–96.5 %)). Nasopharyngeal and sputum samples positive in RT-LAMP contained as few as 10.2 and 23.4 copies per 10 μL, respectively. RT-LAMP showed similar performance to RT-PCR for samples with cycle threshold value below 36. These results indicate that RT-LAMP is a highly reliable and at least equivalent to RT-PCR in utility, and potentially applicable in settings that are more diverse as a point-of-care tool.