Colorimetric loop-mediated isothermal amplification (LAMP) for cost-effective and quantitative detection of SARS-CoV-2: the change in color in LAMP-based assays quantitatively correlates with viral copy number

Anal Methods. 2021 Jan 21;13(2):169-178. doi: 10.1039/d0ay01658f.

Abstract

We demonstrate a loop-mediated isothermal amplification (LAMP) method to detect and amplify SARS-CoV-2 genetic sequences using a set of in-house designed initiators that target regions encoding the N protein. We were able to detect and amplify SARS-CoV-2 nucleic acids in the range of 62 to 2 × 105 DNA copies by this straightforward method. Using synthetic SARS-CoV-2 samples and RNA extracts from patients, we demonstrate that colorimetric LAMP is a quantitative method comparable in diagnostic performance to RT-qPCR (i.e., sensitivity of 92.85% and specificity of 81.25% in a set of 44 RNA extracts from patients analyzed in a hospital setting).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 / diagnosis
  • COVID-19 Nucleic Acid Testing / methods*
  • Colorimetry / methods
  • Coronavirus Nucleocapsid Proteins
  • DNA / analysis
  • DNA / chemistry
  • Fluorescent Dyes / chemistry
  • Humans
  • Intercalating Agents / chemistry
  • Molecular Diagnostic Techniques / methods*
  • Nucleic Acid Amplification Techniques / methods*
  • Phenolsulfonphthalein / chemistry
  • Phosphoproteins
  • RNA / analysis*
  • RNA / chemistry
  • SARS-CoV-2 / chemistry*
  • Viral Load / methods*

Substances

  • Coronavirus Nucleocapsid Proteins
  • Fluorescent Dyes
  • Intercalating Agents
  • Phosphoproteins
  • nucleocapsid phosphoprotein, SARS-CoV-2
  • RNA
  • DNA
  • Phenolsulfonphthalein

Supplementary concepts

  • LAMP assay