Viral Load Quantitation of SARS-coronavirus RNA Using a One-Step Real-Time RT-PCR

Int J Infect Dis. 2006 Jan;10(1):32-7. doi: 10.1016/j.ijid.2005.02.003. Epub 2005 Jul 14.


Introduction: Severe acute respiratory syndrome (SARS) is an emerging infectious disease that first occurred in humans in the People's Republic of China in November 2002 and has subsequently spread worldwide. A novel virus belonging to the Coronaviridae family has been identified as the cause of this pulmonary disease. The severity of the disease combined with its rapid spread requires the development of fast and sensitive diagnostic assays.

Results: A real-time quantitative RT-PCR was designed in the nsp11 region of the replicase 1B domain of the SARS-coronavirus (SARS-CoV) genome. To evaluate this quantitative RT-PCR, cRNA standards were constructed by in vitro transcription of SARS-CoV Frankfurt 1 RNA using T7 RNA polymerase, followed by real-time RT-PCR. The assay allowed quantitation over a range of 10(2) to 10(8) RNA copies per reaction.

Conclusions: Extrapolated to clinical samples, this novel assay has a detection range of 10(4) to 10(10) copies of viral genome equivalents per millilitre. In comparison to the current de facto cRNA Artus Biotech standard, the in-house cRNA standard gives a 100-fold higher absolute quantity, suggesting a possible underestimation of the viral load when using the Artus Biotech standard.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chlorocebus aethiops
  • Coronavirus / genetics
  • Coronavirus / isolation & purification*
  • Coronavirus 229E, Human / genetics
  • Coronavirus 229E, Human / isolation & purification
  • Coronavirus OC43, Human / genetics
  • Coronavirus OC43, Human / isolation & purification
  • Polymerase Chain Reaction / methods*
  • RNA Replicase
  • RNA, Viral / genetics*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Severe Acute Respiratory Syndrome / diagnosis
  • Severe Acute Respiratory Syndrome / virology
  • Vero Cells


  • RNA, Viral
  • RNA Replicase