Rapid and visual detection of 2019 novel coronavirus (SARS-CoV-2) by a reverse transcription loop-mediated isothermal amplification assay

Clin Microbiol Infect. 2020 Jun;26(6):773-779. doi: 10.1016/j.cmi.2020.04.001. Epub 2020 Apr 8.


Objective: To evaluate a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and compare it with RT-PCR.

Methods: We designed primers specific to the orf1ab and S genes of SARS-CoV-2. Total viral RNA was extracted using the QIAamp Viral RNA Mini Kit. We optimized the RT-LAMP assay, and evaluated it for its sensitivity and specificity of detection using real-time turbidity monitoring and visual observation.

Results: The primer sets orf1ab-4 and S-123 amplified the genes in the shortest times, the mean (±SD) times were 18 ± 1.32 min and 20 ± 1.80 min, respectively, and 63°C was the optimum reaction temperature. The sensitivities were 2 × 101 copies and 2 × 102 copies per reaction with primer sets orf1ab-4 and S-123, respectively. This assay showed no cross-reactivity with 60 other respiratory pathogens. To describe the availability of this method in clinical diagnosis, we collected 130 specimens from patients with clinically suspected SARS-CoV-2 infection. Among them, 58 were confirmed to be positive and 72 were negative by RT-LAMP. The sensitivity was 100% (95% CI 92.3%-100%), specificity 100% (95% CI 93.7%-100%). This assay detected SARS-CoV-2 in a mean (±SD) time of 26.28 ± 4.48 min and the results can be identified with visual observation.

Conclusion: These results demonstrate that we developed a rapid, simple, specific and sensitive RT-LAMP assay for SARS-CoV-2 detection among clinical samples. It will be a powerful tool for SARS-CoV-2 identification, and for monitoring suspected patients, close contacts and high-risk groups.

Keywords: COVID-19; Detection; RT-LAMP; SARS-CoV-2; Visual.

Publication types

  • Comparative Study

MeSH terms

  • Betacoronavirus / genetics
  • Betacoronavirus / isolation & purification*
  • COVID-19
  • COVID-19 Testing
  • COVID-19 Vaccines
  • Clinical Laboratory Techniques
  • Coronavirus Infections / diagnosis*
  • Humans
  • Molecular Diagnostic Techniques / methods*
  • Nucleic Acid Amplification Techniques / methods*
  • Pandemics
  • Pneumonia, Viral / diagnosis*
  • Polyproteins
  • Real-Time Polymerase Chain Reaction*
  • SARS-CoV-2
  • Sensitivity and Specificity
  • Spike Glycoprotein, Coronavirus / analysis
  • Viral Proteins / analysis


  • COVID-19 Vaccines
  • Covid-19 aAPC vaccine
  • ORF1ab polyprotein, SARS-CoV-2
  • Polyproteins
  • Spike Glycoprotein, Coronavirus
  • Viral Proteins
  • spike protein, SARS-CoV-2

Supplementary concepts

  • LAMP assay