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

https://doi.org/10.1016/j.jcv.2021.104813Get rights and content

Highlights

  • 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.

Abstract

Background

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.

Objectives

This study aimed to compare the RT-LAMP assay with RT-PCR using the Loopamp™ SARS-CoV-2 Detection Kit.

Study design

One hundred and fifty-one nasopharyngeal swab and 88 sputum samples obtained from individuals with suspected or confirmed COVID-19 were examined.

Results

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.

Conclusions

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.

Abbreviations

COVID-19
coronavirus disease 2019
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
RT-LAMP
reverse transcription loop-mediated isothermal amplification
RT-PCR
reverse transcription-polymerase chain reaction
NIID
the National Institute of Infectious Diseases

Keywords

SARS-CoV-2
COVID-19
Polymerase chain reaction
RT-LAMP
Sputum
Diagnosis

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