Table 2.
Sensitivity and specificity of RAD and automated antigen tests across different ranges of RT-PCR Ct values. Results in grey provide results of all RT-PCR values, including those with a Ct value >33 (min–max range: 12.6–38.2) for sensitivity and specificity.
| Sensitivity | No. of Positive Patients | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Ct Range | n | Biotical (10 min) | Panbio (15 min) |
Panbio (20 min) |
Healgen (15 min) |
Healgen (20 min) |
Roche (15 min) |
Roche (30 min) |
Ortho |
| <15 | 2 | 2 (100%) | 1 (50.0%) | 1 (50.0%) | 2 (100%) | 2 (100%) | 2 (100%) | 2 (100%) | 2 (100%) |
| >15–20 | 34 | 33 (97.1%) | 32 (94.1%) | 32 (94.1%) | 33 (97.1%) | 33 (97.1%) | 33 (97.1%) | 33 (97.1%) | 34 (100%) |
| >20–25 | 22 | 19 (86.4%) | 21 (95.5%) | 21 (95.5%) | 21 (95.5%) | 21 (95.5%) | 21 (95.5%) | 21 (95.5%) | 22 (100%) |
| >25–30 | 19 | 6 (31.6%) | 10 (52.6%) | 10 (52.6%) | 11 (57.9%) | 13 (68.4%) | 10 (52.6%) | 10 (52.6%) | 19 (100%) |
| >30–33 | 3 | 1 (33.3%) | 0 (0.0%) | 0 (0.0%) | 2 (66.7%) | 2 (66.7%) | 0 (0.0%) | 0 (0.0%) | 3 (100%) |
| Total <33 † [95% CI] |
80 | 61 (76.2%) [65.4–85.1%] |
64 (80.0%) [69.6–88.1%] |
64 (80.0%) [69.6–88.1%] |
69 (86.3%) [76.7–92.9%] |
71 (88.8%) [79.7–94.7%] |
66 (82.5%) [72.4–90.1%] |
66 (82.5%) [72.4–90.1%] |
80 (100%) [95.5–100%] |
| >33 | 16 | 3 (18.8%) | 1 (6.3%) | 1 (6.3%) | 1 (6.3%) | 3 (18.8%) | 1 (6.3%) | 1 (6.3%) | 0 (0.0%) |
|
Total (n, %)
[95% CI] |
96 |
64 (66.7%)
[56.3–76.0%] |
65 (67.7%)
[57.4–76.9%] |
65 (67.7%)
[57.4–76.9%] |
70 (72.9%)
[62.9–81.5%] |
74 (77.1%)
[67.4–85.1%] |
67 (69.8%)
[59.6–78.8%] |
67 (69.8%)
[59.6–78.8%] |
80 (83.3%)
[74.4–90.2%] |
| Specificity | No. of Negative Patients | ||||||||
| Neg. RT-PCR ‡ [95% CI] |
108 | 104 (96.3%) [90.8–99.0%] |
107 (99.1%) [95.0–100%] |
107 (99.1%) [95.0–100%] |
105 (97.2%) [92.1–99.4%] |
102 (94.4%) [88.3–97.9%] |
107 (99.1%) [95.0–100%] |
107 (99.1%) [95.0–100%] |
108 (100%) [96.6–100%] |
|
Neg. RT-PCR
[95% CI] |
92 |
91 (98.9%)
[94.1–99.9%] |
92 (100%)
[96.1–100%] |
92 (100%)
[96.1–100%] |
90 (97.8%)
[92.4–99.7%] |
89 (96.7%)
[90.8–99.3%] |
92 (100%)
[96.1–100%] |
92 (100%)
[96.1–100%] |
92 (100%)
[96.1–100%] |
† The cut-off of 33 for the number of Ct has been chosen according to the Common Investigation Protocol for Investigating Suspected SARS-CoV-2 Reinfection of the Centers for Disease Control; ‡ Ct > 33 have been considered negative according to the Common Investigation Protocol for Investigating Suspected SARS-CoV-2 Reinfection of the Centers for Disease Control and Prevention.