Table 4. Sensitivity analysis examining alternative plausible sensitivities and specificities for SARS-CoV-2 IgG antibody tests, Ontario, Canada, 27 March–30 June 2020 (n = 8,902).
| Adjustment for anti-SARS-CoV-2 antibody test characteristics | Collection period and seroprevalence estimates | |||||||
|---|---|---|---|---|---|---|---|---|
| 27 March–30 April | 26–31 May | 5–30 June | ||||||
| SARS-CoV-2 antibody seroprevalence estimate | Sensitivity | Specificity | ||||||
| % | % | % | 95% CI | % | 95% CI | % | 95% CI | |
| Main | 90.4a | 100a | 0.5 | 0.1–1.5 | 1.5 | 0.7–2.2 | 1.1 | 0.8–1.3 |
| Low | 93.5 | 99.6 | 0.08 | 0.0–1.0 | 1.0 | 0.3–1.8 | 0.6 | 0.4–0.9 |
| Medium | 90.4 | 99.8 | 0.3 | 0.0–1.3 | 1.3 | 0.5–2.0 | 0.9 | 0.6–1.1 |
| High | 86.1 | 100 | 0.6 | 0.1–1.6 | 1.6 | 0.8–2.4 | 1.1 | 0.9–1.4 |
CI: confidence interval; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.
a Main analysis.
The tests used were the Abbott Architect SARS-CoV-2 IgG assay (Abbott Laboratories, Abbott Park, Illinois, US), which detects anti-nucleocapsid antibodies, and the VITROS anti-SARS-CoV-2 IgG assay (Ortho-Clinical Diagnostics, Raritan, New Jersey, US), which detects anti-spike antibodies.