A cohort study measuring SARS-CoV-2 seroconversion and serial viral testing in university students

BMC Infectious Diseases

Table 3 Anti-SARS-CoV-2 signal-to-threshold ratios and percent change over time among students who were seropositive by the anti-nucleocapsid assay at semester start

Semester start IgG index value	Semester end IgG index value	Semester start signal-to-threshold ratio	Semester end signal-to-threshold ratio	Percent change (%)	Number of days between baseline and endpoint collection
7.6	5.84	5.43	4.17	− 23	63
5.82	3.44	4.16	2.46	− 41	63
5.65	2.84	4.04	2.03	− 50	69
5.34	4.71	3.81	3.36	− 12	65
5.29	2.82	3.78	2.01	− 47	64
5.29	2.83	3.78	2.02	− 47	67
4.54	2.11	3.24	1.51	− 54	68
3.62	2.82	2.59	2.01	− 22	64
3.52	1.92	2.51	1.37	− 45	64
3.34	1.3	2.39	0.93	− 61	68
2.42	1.23	1.73	0.88	− 49	70
2.31	2.6	1.65	1.86	13	68
1.98	0.66	1.41	0.47	− 67	63
1.54	0.53	1.10	0.38	− 66	68
1.44	0.5	1.03	0.36	− 65	62

IgG index values at baseline and endpoint are shown. Signal-to-threshold ratios were calculated for both baseline and endpoint IgG values based on 1.4 threshold for positivity. Percent change was evaluated for baseline and endpoint IgG index values, and the number of days between baseline and endpoint serum collection are shown

ISSN: 1471-2334