Table 2.
Specificity and limit of detection values of anti-SARS-CoV-2 tests.
| Test No. | Test System (Manufacturer) | N Reactive Samples/ N Tested |
Specificity of Test | Mean COI in Reactive Samples | N Samples in Grey Zone/ N Total |
LoD, BAU/mL |
|
|---|---|---|---|---|---|---|---|
| 1 | DS IFA-ANTI-SARS-CoV-2 (NPO “Diagnostic Systems”, Russia) | version 1 | 6/194 | 96.9% (93.3–98.7%) |
1.73 | 5/194 | n.d.* |
| version 2 | 7/194 | 96.4% (92.6–98.4%) |
1.66 | 3/194 | n.d. | ||
| version 4/5 | 2/281 | 99.3% (97.3–99.9%) |
2.79 | 3/281 | 0.1 | ||
| 2 | SARS-CoV-2-IgG-IFA (National Research Center for Hematology, Moscow, Russia) |
3/281 | 98.9% (96.8–99.8%) |
2.61 | 3/281 | 0.4 | |
| 3 | SARS-CoV-2-IgG-IFA-BEST (Vector-Best, Novosibirsk, Russia) | 4/281 | 98.5% (96.3–99.6%) |
1.80 | 2/281 | 0.5 | |
| 4 | SARS-CoV-2-IgM-IFA-BEST (Vector-Best, Novosibirsk, Russia) | 3/279 | 98,9% (97.3–99.9) |
2.11 | 1/279 | n.d. | |
| 5 | Elecsys Anti-SARS-CoV-2 (Roche Diagnostics, Basal, Switzerland) | 0/281 | 100% (98.4–100%) |
- | 0/281 | n.d. | |
* n.d. = not determined. COI, cut-off index. LOD, limit of detection. BAU/mL, binding antibody units per mL.