Approach 2: AbC-19 results on all EDSAB-HOME samples, compared with immunoassay reference standards
| Reference | AbC-19 positive | AbC-19 negative | Total | Proportion, % (95% CI) |
|---|---|---|---|---|
| “Known positive” samples (n=268) | ||||
| Roche Elecsys: | ||||
| Positive | 244 | 15 | 259 | Sensitivity of AbC-19: 94.2 (90.7 to 96.5) |
| Negative | 4 | 5 | 9 | Agreement: 55.6 (26.7 to 81.1) |
| EUROIMMUN: | ||||
| Positive | 240 | 10 | 250 | Sensitivity of AbC-19: 96.0 (92.8 to 97.8) |
| Negative | 8 | 10 | 18 | Agreement: 55.5 (33.7 to 75.4) |
| Composite reference standard: | ||||
| Positive | 247 | 16 | 263 | Sensitivity of AbC-19: 93.9 (90.3 to 96.2) |
| Negative | 1 | 4 | 5 | Agreement: 80.0 (37.6 to 99.0) |
| Total | 248 | 20 | 268 | Proportion positive on AbC-19: 92.5 (88.8 to 95.1) |
| All “unknown previous infection status” samples (n=2579) | ||||
| Adapted WHO classification: | ||||
| Suspected | 168 | 228 | 396 | 42.4 (37.7 to 47.3) |
| Early probable | 12 | 133 | 145 | 8.3 (4.8 to 13.9) |
| Uncertain | 22 | 123 | 145 | 15.2 (10.2 to 21.9) |
| No | 122 | 1771 | 1893 | 6.4 (5.4 to 7.6) |
| Roche Elecsys: | ||||
| Positive | 300 | 54 | 354 | Sensitivity of AbC-19: 84.7 (80.6 to 88.1) |
| Negative | 24 | 2201 | 2225 | Specificity of AbC-19: 98.9 (98.4 to 99.3) |
| EUROIMMUN: | ||||
| Positive | 296 | 50 | 346 | Sensitivity of AbC-19: 85.5 (81.5 to 88.9) |
| Negative | 28 | 2205 | 2233 | Specificity of AbC-19: 98.7 (98.2 to 99.1) |
| Composite reference standard: | ||||
| Positive | 303 | 69 | 372 | Sensitivity of AbC-19: 81.5 (77.2 to 85.1) |
| Negative | 21 | 2186 | 2207 | Specificity of AbC-19: 99.0 (98.5 to 99.4) |
| Total | 324 | 2255 | 2579 | Proportion positive on AbC-19: 12.6 (11.3 to 13.9) |
Results are presented separately for “known positive” (WHO “confirmed” category: n=268) and “unknown previous infection status” (all other EDSAB-HOME participants: n=2579) samples. Composite reference standard was “positive on at least one of Roche Elecsys or EUROIMMUN versus negative on both.”