TABLE 2.
Sensitivities and specificities of the qSAT antibody assays for negative controls plus either all positive samples or positive samples at different times since the onset of symptoms and different thresholds targeting specificities of 100%, 99%, and 98%a
| Antibody/antigen combination | AUC | % specificity | % sensitivity |
|---|---|---|---|
| All samples | |||
| IgG N + IgM RBD + IgA RBD + IgM S2 | 0.925 | 100 | 80.77 |
| IgG N + IgM RBD + IgA RBD + IgM S2 + IgG N Ct | 0.922 | 100 | 80.77 |
| IgG N + IgA S2 + IgM RBD + IgM S + IgM S2 + IgA N | 0.919 | 100 | 80.77 |
| IgG N + IgA S2 + IgM RBD | 0.920 | 99.22 | 82.69 |
| IgG N + IgA S2 + IgM RBD + IgG S + IgA N + IgA S | 0.919 | 99.22 | 82.69 |
| IgG N + IgM RBD + IgA S | 0.917 | 99.22 | 82.69 |
| IgG N + IgA S2 + IgM RBD | 0.920 | 98.44 | 82.69 |
| IgG N + IgA S2 + IgM RBD + IgG S + IgA S | 0.919 | 98.44 | 82.69 |
| IgG N + IgA S2 + IgM RBD + IgG S + IgA N + IgA S | 0.918 | 98.44 | 82.69 |
| ≥7 days since onset of symptoms | |||
| IgA S2 + IgM S + IgA RBD | 0.975 | 100 | 92.94 |
| IgA S2 + IgM S | 0.975 | 100 | 92.94 |
| IgA S2 + IgM S + IgM S2 + IgA RBD | 0.971 | 100 | 92.94 |
| IgA S2 + IgG S2 + IgM S + IgA RBD | 0.981 | 99.22 | 92.94 |
| IgM RBD + IgA S2 + IgG S + IgM S + IgM S2 + IgA RBD | 0.980 | 99.22 | 92.94 |
| IgM RBD + IgA S2 + IgG S | 0.980 | 99.22 | 92.94 |
| IgA S2 + IgG S + IgM S | 0.983 | 98.44 | 92.94 |
| IgG S2 + IgM S + IgA RBD | 0.983 | 98.44 | 92.94 |
| IgA S2 + IgG S2 + IgM S + IgA RBD | 0.981 | 98.44 | 92.94 |
| ≥14 days since onset of symptoms | |||
| IgM RBD + IgG N + IgA S | 0.977 | 100 | 95.78 |
| IgA S2 + IgM S + IgG N + IgG N Ct + IgM S2 | 0.975 | 100 | 95.78 |
| IgA S2 + IgG N + IgM S2 | 0.975 | 100 | 95.78 |
| IgM RBD + IgG S + IgM S + IgG N | 0.992 | 99.22 | 95.78 |
| IgM RBD + IgG S + IgA S2 + IgM S + IgG N + IgG RBD + IgG N Ct | 0.992 | 99.22 | 95.78 |
| IgM RBD + IgG S + IgA S2 + IgG N + IgM S2 | 0.991 | 99.22 | 95.78 |
| IgG S + IgG RBD + IgG N Ct + IgM S2 | 0.985 | 98.44 | 97.18 |
| IgG S + IgG RBD | 0.984 | 98.44 | 97.18 |
| IgG S + IgA S2 + IgG RBD + IgM S2 + IgA RBD | 0.983 | 98.44 | 97.18 |
| ≥21 days since onset of symptoms | |||
| IgG S + IgM RBD + IgG N + IgM S + IgM S2 | 0.999 | 100 | 95.65 |
| IgM RBD + IgG N Ct + IgM S2 + IgA RBD | 0.995 | 100 | 95.65 |
| IgM RBD + IgM S2 + IgA S | 0.992 | 100 | 95.65 |
| IgG S + IgG RBD + IgM RBD | 0.999 | 99.22 | 97.83 |
| IgG S + IgG RBD + IgM RBD + IgG N + IgM S2 | 0.999 | 99.22 | 97.83 |
| IgG S + IgG RBD + IgM RBD + IgG N + IgM S2 + IgA RBD | 0.999 | 99.22 | 97.83 |
| IgG S + IgG RBD + IgM RBD | 0.999 | 98.44 | 100 |
| IgG S + IgA S2 + IgG RBD + IgM RBD + IgM S2 + IgA RBD + IgA S | 0.999 | 98.44 | 100 |
| IgG S + IgA S2 + IgM RBD + IgM S2 + IgA RBD | 0.999 | 98.44 | 100 |
| ≥28 days since onset of symptoms | |||
| IgA S2 + IgG N + IgM S2 | 0.9997 | 100 | 95.83 |
| IgA S2 + IgM S + IgG N Ct + IgM RBD + IgM S2 | 0.9997 | 100 | 95.83 |
| IgG N + IgG N Ct + IgM RBD | 0.9997 | 100 | 95.83 |
| IgA S2 + IgG N + IgM S2 | 0.9997 | 99.22 | 100 |
| IgA S2 + IgM S + IgG N Ct + IgM RBD + IgM S2 | 0.9997 | 99.22 | 100 |
| IgG N + IgG N Ct + IgM RBD | 0.9997 | 99.22 | 100 |
| IgA S2 + IgG N + IgM S2 | 0.9997 | 98.44 | 100 |
| IgA S2 + IgM S + IgG N Ct + IgM RBD + IgM S2 | 0.9997 | 98.44 | 100 |
| IgG N + IgG N Ct + IgM RBD | 0.9997 | 98.44 | 100 |
a
The top 3 best-performing signatures for each category are shown. AUC, area under the curve; N Ct, C terminus of N.