Table 3

Approach 2: AbC-19 results on all EDSAB-HOME samples, compared with immunoassay reference standards

ReferenceAbC-19 positiveAbC-19 negativeTotalProportion, % (95% CI)
“Known positive” samples (n=268)
Roche Elecsys:
 Positive24415259Sensitivity of AbC-19: 94.2 (90.7 to 96.5)
 Negative459Agreement: 55.6 (26.7 to 81.1)
EUROIMMUN:
 Positive24010250Sensitivity of AbC-19: 96.0 (92.8 to 97.8)
 Negative81018Agreement: 55.5 (33.7 to 75.4)
Composite reference standard:
 Positive24716263Sensitivity of AbC-19: 93.9 (90.3 to 96.2)
 Negative145Agreement: 80.0 (37.6 to 99.0)
Total
24820268Proportion positive on AbC-19: 92.5 (88.8 to 95.1)
All “unknown previous infection status” samples (n=2579)
Adapted WHO classification:
 Suspected16822839642.4 (37.7 to 47.3)
 Early probable121331458.3 (4.8 to 13.9)
 Uncertain2212314515.2 (10.2 to 21.9)
 No122177118936.4 (5.4 to 7.6)
Roche Elecsys:
 Positive30054354Sensitivity of AbC-19: 84.7 (80.6 to 88.1)
 Negative2422012225Specificity of AbC-19: 98.9 (98.4 to 99.3)
EUROIMMUN:
 Positive29650346Sensitivity of AbC-19: 85.5 (81.5 to 88.9)
 Negative2822052233Specificity of AbC-19: 98.7 (98.2 to 99.1)
Composite reference standard:
 Positive30369372Sensitivity of AbC-19: 81.5 (77.2 to 85.1)
 Negative2121862207Specificity of AbC-19: 99.0 (98.5 to 99.4)
Total32422552579Proportion 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.”