Table 2.
Detection of SARS-CoV-2 RNA in Respiratory Specimens from COVID-19 Cases
| Collection Date | Sample Types | COVID-19 Cases |
||
|---|---|---|---|---|
| Severe | Mild | p Values | ||
| 0–7 d.a.o. | ||||
| Positive rate (n/N, %) | oropharyngeal | 40/55 (72.7) | 84/158 (53.2) | 0.0116 |
| nasopharyngeal | 58/68 (85.3) | 195/314 (62.1) | 0.0002 | |
| sputum | 14/16 (87.5) | 38/46 (82.6) | >0.9999 | |
| BALF | 2/2 (100.0) | 0/0 (0) | >0.9999 | |
| Ct values (median; range) | oropharyngeal | 29.5 (18.86–36.32) | 29.50 (15.46–37.38) | 0.8957 |
| nasopharyngeal | 29.3 (19.19–37.66) | 29 (14.57–38) | 0.1974 | |
| Sputum | 26 (19–32.2) | 28 (17.94–38) | 0.2707 | |
| BALF | 22.5 (21–24) | – | N/A | |
| 8–14 d.a.o. | ||||
| Positive rate (n/N, %) | oropharyngeal | 39/81 (48.1) | 48/105 (45.7) | 0.7685 |
| nasopharyngeal | 117/170 (68.8) | 241/454 (53.1) | 0.0004 | |
| Sputum | 29/39 (74.4) | 80/109 (73.4) | >0.9999 | |
| BALF | 13/13 (100) | 0/2 (0) | 0.0095 | |
| Ct values (median; range) | oropharyngeal | 30.22 (20.73–36.25) | 31.1 (20.81–37.06) | 0.5956 |
| nasopharyngeal | 30.92 (19.7–38) | 32.74 (18.44–38) | <0.0001 | |
| Sputum | 30 (15.42–38) | 31.23 (19.66–38) | 0.221 | |
| BALF | 27 (19–35) | – | N/A | |
| ≥15 d.a.o. | ||||
| Positive rate (n/N, %) | oropharyngeal | 30/95 (31.6) | 14/65 (21.5) | 0.4621 |
| nasopharyngeal | 129/379 (34.0) | 192/846 (22.7) | <0.0001 | |
| Sputum | 64/167 (38.3) | 94/319 (29.5) | 0.053 | |
| BALF | 30/47 (63.8) | 0/2 (0) | 0.375 | |
| Ct values (median; range) | oropharyngeal | 34.6 (24.27–38) | 34.8 (27.84–38) | 0.5651 |
| nasopharyngeal | 33.36 (21.8–38) | 35 (23.71–38) | 0.0257 | |
| Sputum | 33.32 (23–38) | 35.2 (19–38) | 0.0967 | |
| BALF | 31 (20–37) | – | N/A | |
N/A, not applicable; BALF, bronchoalveolar lavage fluid; d.a.o., days after illness onset.