Table 1.
A summary of the performance characteristics of eight commercial COVID-19 serology assays.
| Assay | Wantai Ig | Wantai IgM | Euroimmun IgG | Euroimmun IgA | Liaison | Cellex | Intec | Orient/Healgen | |
|---|---|---|---|---|---|---|---|---|---|
| Platform | ELISA | ELISA | ELISA | ELISA | CLIA | RDT | RDT | RDT | |
| Antigen | RBD | RBD | S1 | S1 | S1 and S2 | S and N | N | S and N | |
| Specificity | |||||||||
| n/N | 145/146 | 144/146 | 156/157 | 147/157 | 119/132 | 97/98 | 83/98 | 87/98 | |
| Value | 0.99 | 0.99 | 0.99 | 0.94 | 0.90 | 0.99 | 0.85 | 0.88 | |
| 95% CI | 0.96–1.0 | 0.951–1.0 | 0.97–1.0 | 0.89–0.97 | 0.84–0.95 | 0.95–1.0 | 0.76–0.91 | 0.80–0.94 | |
| Sensitivity | |||||||||
| Overall | n/N | 186/187 | 167/185 | 61/75 | 73/75 | 134/165 | 101/113 | 102/113 | 113/113 |
| Value | 0.99 | 0.90 | 0.81 | 0.97 | 0.81 | 0.89 | 0.90 | 1.0 | |
| 95% CI | 0.97–1.0 | 0.85–0.94 | 0.71–0.89 | 0.91–1.0 | 0.74–0.87 | 0.82–0.94 | 0.83–0.95 | 0.97–1.0 | |
| >14 dps | n/N | 117/117 | 100/115 | 26/27 | 27/27 | 95/104 | 63/67 | 55/65 | 67/67 |
| Value | 1.0 | 0.87 | 0.96 | 1.0 | 0.91 | 0.94 | 0.84 | 1.0 | |
| 95% CI | 0.97–1.0 | 0.79–0.93 | 0.81–1.0 | 0.87–1.0 | 0.84–0.96 | 0.85–0.98 | 0.74–0.92 | 0.95–1.0 | |
| Mild | n/N | 64/64 | 54/62 | 1/3 | 3/3 | 46/55 | 33/37 | 26/36 | 37/37 |
| Value | 1.0 | 0.87 | 0.33 | 1.0 | 0.84 | 0.89 | 0.72 | 1.0 | |
| 95% CI | 0.94–1.0 | 0.76–0.94 | 0.0084–0.91 | 0.29–1.0 | 0.71–0.92 | 0.75–0.97 | 0.55–0.86 | 0.91–1.0 | |
| Overall PPV | |||||||||
| Population prevalence | 4% | 0.86 | 0.73 | 0.84 | 0.39 | 0.26 | 0.78 | 0.20 | 0.26 |
| 50% | 0.99 | 0.99 | 0.99 | 0.94 | 0.89 | 0.99 | 0.86 | 0.89 | |
| 95% | 1.0 | 1.0 | 1.0 | 1.0 | 0.99 | 1.0 | 0.99 | 0.99 | |
| Overall NPV | |||||||||
| Population prevalence | 4% | 1.0 | 1.0 | 0.99 | 1.0 | 0.99 | 1.0 | 1.0 | 1.0 |
| 50% | 0.99 | 0.91 | 0.84 | 0.97 | 0.83 | 0.9 | 0.9 | 1.0 | |
| 95% | 0.91 | 0.35 | 0.22 | 0.65 | 0.20 | 0.33 | 0.31 | 1.0 | |
Sensitivity of the assays was determined by comparing the outcome to virus neutralization (PRNT> 20). Patients were considered mild if they have not been admitted to a hospital. The PPV was calculated for 3 scenarios: 4 % seroprevalence in a general population. 50% seroprevalence in a high risk sub-population and 90% seroprevalence in hospitalized patients suspect for COVID-19. Ig: immunoglobulin, ELISA: enzyme linked immunosorbent assay, CLIA: chemiluminescence immune assay, RDT: rapid diagnostic test, n:number of positives, N: total number tested, CI: confidence interval, dps: days post onset of symptoms, PPV: positive predictive value, NPV: negative predictive value, PRNT: plaque reduction neutralization test.