Table 1.

Comparison of RT-PCR and rapid antigen detection kits for the limit of detection of SARS−COV-2 virus.

Dilutionb	Test resultsa
	RAD kit				RT-PCRc
	BIOCREDIT	Coris	NADAL	Standard Q
10−1	POS	POS	POS	POS	15.15
10−2	POS	POS	POS	POS	18.44
10−3	NEG	NEG	NEG	POS	21.54
10−4	NEG	NEG	NEG	POS	24.64
10−5	ND	ND	ND	POS	28.67
10−6	ND	ND	ND	NEG	31.90
10−7	ND	ND	ND	ND	34.87
10−8	ND	ND	ND	ND	NEG

^aPOS, positive; NEG, negative; ND, not done.

^bSerial tenfold dilution of the respiratory specimen, NPA & TS, obtained from the Hong Kong COVID-19 patient, hCoV-19/Hong Kong/VM20030475/2020.

^cRT-PCR were tested twice with identical results. The Ct values shown were the mean of both runs.