Table 2.

RT-qPCR Ct values for different sample types.

Comparison	Sample	N	Range of Ct values for E gene	Median Ct value	Mean ± standard deviation t value	p-value	Correlation coefficient
NPS vs. buccal swab	NPS	43	12.10–34.40	21.8	21.51 ± 4.96	0.001*	0.342 (p = 0.025)
	Buccal swab	43	17.54–37.72	31.61	31.06 ± 4.09
Buccal swab vs. saliva	Buccal swab	29	17.54–37.72	31.61	30.88 ± 4.68	0.004*	0.464 (p = 0.011)
	Saliva	29	16.38–36.65	27.02	27.29 ± 4.56
NPS vs. saliva	NPS	39	12.10–36.0	21.8	22.04 ± 5.88	0.001*	0.359 (p = 0.025)
	Saliva	39	16.38–36.65	28.06	28.16 ± 4.48

N: number of positive samples common to both groups, Ct: Cycle threshold; NPS: Nasopharyngeal swab; RT-qPCR: reverse transcription quantitative polymerase chain reaction; *: statistically significant