SARS-CoV-2 RNA (RdRp gene) test results from various sources within 2 days of COVID-19 diagnosis of the index case and the secondary case.
| Specimens | Index case | Secondary case | ||
| Qualitative* | Ct* | Qualitative* | Ct* | |
| Nasopharynx | Positive | 21.3 | Positive | 19.1 |
| Oropharynx | Positive | 28.0 | Positive | 30.0 |
| Sputum | Positive | 17.7 | Positive | 18.5 |
| Saliva | Borderline | 35.1 | Positive | 25.0 |
| Stool | Negative | – | Negative | – |
| Plasma | Negative | – | Negative | – |
*Ct value of ≤35 is positive and >40 is negative; value in between is reported as borderline.
Ct, cycle threshold; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.