Table 3.
Specificity of Assaysa
| All Expected Negative Samplesb | Prepandemic and Cross-Reactivity | Clinical RT-PCR Negativeb | ||||
|---|---|---|---|---|---|---|
| Manufacturer | Positive/Samples, No. | Specificity (95% CI) | Positive/Samples, No. | Specificity (95% CI) | Positive/Samples, No. | Specificity (95% CI) |
| DiaSorin | 6/185 | 96.8 (93.1-98.8) | 4/134 | 97.0 (92.5-99.2) | 2/51 | 96.1 (86.5-99.5) |
| EUROIMMUN, indeterminate = positive | 16/188 | 91.5 (86.6-95.1) | 9/137 | 93.4 (87.9-97.0) | 7/51 | 86.3 (73.7-94.3) |
| EUROIMMUN, indeterminate = negative | 7/188 | 96.3 (92.5-98.5) | 5/137 | 96.4 (91.7-98.8) | 2/51 | 96.1 (86.5-99.5) |
| Roche | 0/188 | 100 (98.1-100) | 0/137 | 100 (97.3-100) | 0/51 | 100 (93.0-100) |
| Siemens | 0/188 | 100 (98.1-100) | 0/137 | 100 (97.3-100) | 0/51 | 100 (93.0-100) |
CI, confidence interval; RT-PCR, reverse transcription polymerase chain reaction.
aSpecificity is calculated for all samples expected to be negative and pertinent subgroups. For EUROIMMUN, calculations are provided for categorizing indeterminate results as positive or negative.
bExcluding two samples that were positive on all assays and adjudicated as presumptive RT-PCR testing false negatives.