TABLE 4.
Anti-SARS-CoV-2 IgG assay sensitivity in convalescent-phase sera and in individual patients tested ≥15 days post-symptom onset or first positive SARS-CoV-2 RT-PCR result
| Assay | Serum samples (n = 84)a
|
Individuals patients (n = 37)b
|
||
|---|---|---|---|---|
| % Positive (no.) | 95% CI | % Positive (no.)c | 95% CI | |
| Abbott | 92.9% (78/84) | 85%–97% | 97.3% (36/37) | 85%–100% |
| Epitope | 88.1% (74/84) | 79.3%–93.6% | 73% (27/37) | 56.9%–84.8% |
| Euroimmun | 97.6% (82/84) | 91.2%–99.9% | 94.6% (35/37) | 81.4%–99.4% |
| Ortho-Clinical | 98.8% (83/84) | 92.9%–100% | 97.3% (36/37) | 85%–100% |
The 84 serum samples included 61 samples collected at least 15 days post-symptom onset from inpatients and 23 samples collected 20 days or more post-initial positive SARS-CoV-2 RT-PCR result in outpatients (see Table 3).
The 37 individual patients included all 23 outpatients with sera collected 20 days or more post-initial positive SARS-CoV-2 RT-PCR result and 14 inpatients who had a serum sample collected 15 days or more post-symptom onset. Patients were counted as positive if at least one sample collected 15 days or more post-onset or first RT-PCR was positive.
One patient was negative by the Euroimmun and Ortho-Clinical assays, and a second patient was negative by both the Epitope and Abbott assays. One and two patients, respectively, were indeterminate by the Euroimmun and Epitope assays but positive by all other assays.