Table 3.
Positive and negative percent agreements between in-house ELISA and two commercially available serological assays.
| Type of anti-SARS-CoV-2 antibody detection assays compared | PPA | (95% CI) | NPA | (95% CI) | ||
|---|---|---|---|---|---|---|
| Lower | Upper | Lower | Upper | |||
| In-house ELISA vs. Elecsys CLIA | 81.7 | 79.5 | 84 | 80.1 | 77.8 | 82.4 |
| In-house ELISA vs. Rapid LFA test (IgG + IgM) | 83 | 80.8 | 85.1 | 70.4 | 67.8 | 73.1 |
| In-house ELISA vs. Rapid LFA test IgM only | 51.8 | 48.8 | 54.6 | 80.5 | 78.3 | 82.6 |
| In-house ELISA vs. Rapid LFA test IgG only | 80.5 | 78.2 | 82.8 | 77.8 | 75.4 | 80.2 |
| Rapid LFA test (IgG + IgM) vs Elecsys | 81.1 | 78.8 | 83.4 | 91.9 | 90.3 | 93.5 |
| Elecsys CLIA vs. Rapid test IgM only | 54.6 | 51.7 | 57.5 | 85.3 | 83.2 | 87.4 |
| Elecsys CLIA vs. Rapid LFA test IgG only | 89.4 | 83.2 | 94.8 | 89.4 | 87.6 | 91.2 |
NPA: Negative percent agreement; PPA: Positive Percent Agreement; CI: Confidence interval.