Table 4.

Sensitivities for the commercial assays in relation to sampling time following PCR positivity using the two-step ELISA as reference.

Assay	Sensitivity (95% CI), Sampling 1–30 Days after Positive PCR Test, n = 36	Sensitivity (95% CI), Sampling 31–60 Days after Positive PCR Test, n = 76	Sensitivity (95% CI), Sampling 61–90 Days after Positive PCR Test, n = 15	Sensitivity (95% CI), Sampling 91–180 Days after Positive PCR Test, n = 25	Sensitivity (95% CI), Sampling 181–325 Days after Positive PCR Test, n = 43
Wantai RBD total antibody	97.1% (85.5–99.5)	98.7% (92.9–99.8)	93.3% (70.2–98.8)	100% (86.7–100)	97.7% (87.9–99.6)
Liaison S1/S2 IgG	65.7% (49.2–79.2)	93.4% (85.5–97.2)	86.7% (62.1–96.3)	88.0% (70.0–95.8)	90.7% (78.4–96.3)
Alinity i nucleocapsid IgG	74.3% (57.9–85.8)	96.1% (89.0–98.6)	66.7% (41.7–84.8)	52.0% (33.5–70.0)	37.2% (24.4–52.1)

Abbreviations: RBD: receptor-binding domain, S1/S2: subunit 1/subunit 2, Ig: immunoglobulin, CI: confidence interval.