TABLE 3.

Clinical performance of the LIAISON SARS-CoV-2 S1/S2 IgG assay using 9 and 15 AU/ml as cutoffs based on RT-PCR diagnoses

Cutoff (AU/ml)	Sensitivity or specificity	Time period or test result	LIAISON SARS-CoV-2 S1/S2 IgG assay
			% of positive samples	95% CI	No. of samples
9	Sensitivity	≤5 days	33.3	23.4–44.5	84
		>5 days	91.3	85.0–95.6	127
	Specificity	Pre-COVID-19	97.1	96.0–98.0	1,140
		All negative results	97.0	95.9–97.8	1,380
15	Sensitivity	≤5 days	22.6	14.2–33.0	84
		>5 days	88.2	81.3–93.2	127
	Specificity	Pre-COVID-19	98.5	97.6–99.1	1,140
		All negative results	98.1	97.2–98.8	1,380