Table 2.
Positivity, specificity, NPV and PPV of examined SARS-CoV-2 serology assays.
| specificity |
positivity |
NPV |
PPV |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| (n = 320) | 1−10 d (n = 37) | > 10 d (n = 38) | prevalence 0.8 % |
||||||||
| 1−10 d | > 10 d | 1−10 d | > 10 d | ||||||||
| % | 95 % CI | % | 95 % CI | % | 95 % CI | % | % | % | % | ||
| Euroimmun | |||||||||||
| 99.1 | (97.3−99.7) | 27.0 | (15.4−43.0) | 70.3 | (54.2−82.5) | 99.4 | 99.8 | 19.5 | 38.6 | ||
| Diasorin | |||||||||||
| 99.1 | (97.3−99.7) | 29.7 | (17.5−45.8) | 68.4 | (52.5−80.9) | 99.4 | 99.7 | 21.0 | 38.0 | ||
| Roche | |||||||||||
| 99.7 | (98.3−100) | 46.0 | (31.0−61.6) | 79.0 | (63.7−88.9) | 99.6 | 99.8 | 55.3 | 68.0 | ||
| Wantai | |||||||||||
| 99.4 | (97.8−100) | 73.0 | (57.0−84.6) | 81.6 | (66.6−90.8) | 99.8 | 99.9 | 49.5 | 52.3 | ||
| Siemens | |||||||||||
| 100 | (98.8−100) | 35.1 | (21.8−51.2) | 73.7 | (58.0−85.0) | 99.5 | 99.8 | 100 | 100 | ||
To determine positivity rates and specificity, samples from SARS-CoV-2 PCR positive patients (n = 75) collected in March and April of 2020 and samples from pre-pandemic blood donations made in March of 2017 (n = 320) were tested with each assay. NPV and PPV were calculated for a prevalence of 0.8 % according to our local currently low prevalence setting (Hamburg, Germany). Patients were grouped according to the time between onset of symptoms and date of blood sampling in days (1−10 days and >10 days).
Abbreviations: CI, confidence interval; d, days; NPV, negative predictive value; PPV, positive predictive value.