Table 3.

Assay sensitivity by time since onset of symptoms for each SARS-CoV-2 antigen calculated using the COVID-19 cohort with verified time between onset of symptoms and blood sampling. Time was divided into 0-7 days, over 7 days, over 14 days and over 21 days since the onset of symptoms.

Antigen	Group		n	Positive	Negative	Sensitivity (95 % CI) (%)
CoV-2 S	Total		196	178	18	90.8 % (86.0–94.1)
	Time since onset of symptoms	0−7 days	20	15	5	75.0% (53.1–88.8)
		Over 7 days	148	138	10	93.2% (88.0–96.3)
		Over 14 days	78	75	3	96.2 % (89.3–99.0)
		Over 21 days	47	46	1	97.9 % (88.8–99.9)
CoV-2 RBD	Total		196	153	43	78.1% (71.8–83.3)
	Time since onset of symptoms	0−7 days	20	12	8	60.0% (38.7–78.1)
		Over 7 days	148	119	29	80.4% (73.3–86.0)
		Over 14 days	78	71	7	91.0% (82.6–95.6)
		Over 21 days	47	44	3	93.6% (82.8–97.8)
CoV-2 N	Total		196	143	53	73.0% (66.3–78.7)
	Time since onset of symptoms	0−7 days	20	12	8	60.0% (38.7–78.1)
		Over 7 days	148	106	42	71.6% (63.9–78.3)
		Over 14 days	78	66	12	84.6% (75.0–91.0)
		Over 21 days	47	41	6	87.2% (74.8–94.0)