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Authors:  Jung et al.                   

Link to paper:       

Journal/ Pre-Print: BioRXiv


This study compares the sensitivity of different primer probe sets recommended by the World Health Organisation (WHO) for the confirmation of SARS-CoV-2. Sensitivity is required for the early diagnosis of SARS-CoV-2. Of the WHO recommended SARS-CoV-2 primers, ORF1 and N gene primers were assessed in this study. Using serial dilutions of SARS-CoV-2 RNA isolated from infected Vero cells, the sensitivity of different primer sets was assessed using quantitative RT-PCR. This study concluded that ORF1ab (China), 2019-nCoV_N2 (USA), 2019-nCoV_N3 (USA), and NIID_2019-nCoV_N (Japan) sets may be recommended for the laboratory confirmation of SARS-CoV-2.

Research highlights

  1. CT values compared at a concentration of 15 copies per reaction
  2. Sensitivity of primer probe sets was consistent across serial dilutions of RNA samples.
  3. ‘2019-nCoV_N2, N3’ of USA most sensitive N gene set comparable to that of

NIID_2019-nCOV_N (Japan)

  1. ‘ORF1ab’ of China most sensitive ORF1 gene set
  2. Appropriate combination of above best for most sensitive confirmation of SARS-CoV-2

Research Impact:

Provides researchers with the most sensitive primer sets for the early diagnosis of SARS-CoV-2.


African green monkey kidney Vero cells (ATCC CCL-81) were infected with a clinical isolate SARS-CoV-2 (BetaCoV/Korea/KCDC03/2020) provided from Korea CDC.

RNA was isolated and purified using QiAMP Qiagen kit.

qRT-PCR was used to assess primer sensitivity.

Strengths and weaknesses of the paper:


Quality of the assays

Sensitivity of primer probe sets was consistent across serial dilutions of RNA samples.



Could have done more repeats as can’t have a loading control CT to adjust to.

Only one set of primers used to reverse transcribe RNA.