Table 1.
Assay sensitivity for the SARS-CoV-2 antigen test in the evaluation collective (predominantly samples of symptomatic (and PCR-positive) patients during hospitalization) as well as the specificity in the asymptomatic screening cohort
| Cut-Off ≥ 200 AU/mL | |||||||
|---|---|---|---|---|---|---|---|
| n | Antigen positive | Antigen negative | Sensitivity [%] | 95% CI | specificity [%] | 95% CI | |
| Covid19 patients | 196 | 68 | 128 | 40.2 | 33.1–58.4 | n.d | n.d |
| Ct < 25 | 57 | 52 | 5 | 91.2 | 81–96.2 | n.d | n.d |
| 25 ≤ Ct < 30 | 47 | 14 | 33 | 29.8 | 18.7–44 | n.d | n.d |
| Ct ≥ 30 | 65 | 2 | 63 | 3.1 | 0.9–10.6 | n.d | n.d |
| Negative | 27 | 0 | 27 | n.d | n.d | 100.0 | n.d |
| Screening patients | 1636 | 4 | 1632 | n.d | n.d | ||
| Correctly identified | 4 | 1632 | n.d | n.d | 100.0 | 99.7–100.0 | |
| Cut-Off ≥ 100 AU/mL | |||||||
|---|---|---|---|---|---|---|---|
| n | Antigen positive | Antigen negative | Sensitivity [%] | 95% CI | Specificity [%] | 95% CI | |
| Covid19 patients | 196 | 84 | 112 | 49.7 | 42.3–57.2 | n.d | n.d |
| Ct < 25 | 57 | 54 | 3 | 94.7 | 85.6–98.2 | n.d | n.d |
| 25 ≤ Ct < 30 | 47 | 23 | 24 | 48.9 | 35.3–62.8 | n.d | n.d |
| Ct ≥ 30 | 65 | 7 | 58 | 10.8 | 5.3–20.6 | n.d | n.d |
| Negative | 27 | 0 | 27 | n.d | n.d | 100.0 | n.d |
| Screening patients | 1636 | 32 | 1604 | n.d | n.d | ||
| Correctly identified | 4 | 1604 | n.d | n.d | 98.3 | 97.5–98.8 | |
Sensitivity and specificity are given for the cut-off of 200 AU/mL, as recommended by the manufacturer, as well as for the cut-off 100. Confidence intervals were computed using Wilson score interval [20]
AU arbitrary units; relative light units converted to TCID50/mL equivalents by the manufacturer. n.d. not determined