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Table. 2.

Table. 2.

Comparison of Ct values in paired upper and lower respiratory tract samples obtained from newly diagnosed COVID-19 patients (N =1,916)

SARS-CoV-2 target gene NPS vs. sputum (N=909) NPS/OPS vs. sputum (N=1,007)


Ct value, Median (IQR) Ct difference, Median (IQR) Ct value, Median (IQR) Ct difference, Median (IQR)




NPS Sputum Sputum-NPS P* NPS/OPS Sputum Sputum-NPS P*
E 24.61 (19.20-29.51) 24.57 (19.57-29.06) 0.22 (-0.16-0.59) >0.05 24.69 (18.59-29.65) 24.82 (19.24-29.52) 0.19 (-0.14-0.51) >0.05
RdRp 25.65 (20.33-30.42) 25.82 (20.95-30.12) 0.28 (-0.07-0.64) >0.05 25.66 (19.97-30.86) 25.89 (20.49-30.72) 0.29 (-0.03-0.61) >0.05
N 26.97 (21.58-31.29) 27.12 (22.31-31.34) 0.49 (0.11-0.88) 0.034 26.89 (21.22-31.79) 27.18 (21.97-31.95) 0.43 (0.07-0.80) >0.05

*Bonferroni-corrected P.

Abbreviations: COVID-19, coronavirus disease 2019; Ct, threshold cycle; E, envelope; IQR, interquartile range; N, nucleocapsid; NPS, nasopharyngeal swab; OPS, oropharyngeal swab; RdRp, RNA-dependent RNA polymerase; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Ann Lab Med 2021;41:225~229 https://doi.org/10.3343/alm.2021.41.2.225

© Ann Lab Med