Table 3.

Sensitivity and specificity of salivary IgG for detection of prior SARS-CoV-2 infection.

Antigen	Isotype	Threshold (AU/mL)	Sensitivity at < 2 weeks	Sensitivity at 2–4 weeks	Sensitivity at 4–8 weeks	Specificity
SARS-CoV-2 Spike	IgG	0.963	40.7% (22.4–61.2%)	95.8% (78.9–99.9%)	92.6% (75.7–99.1%)	92.4% (87.4–95.9%)
SARS-CoV-2 N	IgG	3.18	48.1% (28.7–68.1%)	79.2% (57.8–92.9%)	92.6% (75.7–99.1%)	90.7% (85.3–94.6%)
SARS-CoV-2 S1 RBD	IgG	0.244	66.7% (46.0–83.5%)	91.7% (73.0–99.0%)	92.6% (75.7–99.1%)	64.5% (56.9–71.7%)

Point estimates and 95% confidence intervals (indicated in parentheses) were computed at pre-established thresholds.