Table 4.
Sensitivities of STANDARD Q COVID-19 Ag test according to Ct values for E and RdRp.
| Nasopharyngeal Specimen | Nasal Cavity Specimen | |||||||
|---|---|---|---|---|---|---|---|---|
| Ct Value | N | Sensitivity, % | 95% CI | p * | N | Sensitivity, % | 95% CI | p * |
| Overall | 58 | 81.7 | 72.7–90.7 | 55 | 77.5 | 67.8–87.2 | 0.82 | |
| E | ||||||||
| Ct < 15 | 16 | 100.0 | 100.0–100.0 | 16 | 100.0 | 100.0–100.0 | ||
| 15 ≤ Ct < 25 | 38 | 95.0 | 88.3–100.0 | <0.01 | 35 | 87.5 | 77.3–97.8 | 0.01 |
| 25 ≤ Ct ≤ 35 | 4 | 26.7 | 4.3–49.1 | <0.01 | 4 | 26.7 | 4.3–49.1 | <0.01 |
| RdRp | ||||||||
| Ct < 15 | 22 | 100.0 | 100.0–100.0 | 21 | 95.5 | 86.8–100.0 | ||
| 15 ≤ Ct < 25 | 33 | 91.7 | 82.6–100.0 | 0.06 | 31 | 86.1 | 74.8–97.4 | 0.07 |
| 25 ≤ Ct ≤ 35 | 3 | 23.1 | 0.2–46.0 | <0.01 | 3 | 23.1 | 0.2–46.0 | <0.01 |
* p for comparison between 15 ≤ Ct < 25 and 25 ≤ Ct ≤ 35 vs. Ct value <15; Abbreviations: N, number of COVID-19 Ag positives; CI, confidence interval.