TABLE 3.
Stability of frozen SARS-CoV-2 RNA detected by the Quest EUA rRT-PCRa
| Medium or sample type | Detectorb | Mean CT (SD) of 5 frozen (−10 to −30°C) specimens on day: |
||||
|---|---|---|---|---|---|---|
| 0 | 3 | 5 | 7 | 14 | ||
| UTM | N1 | 31.8 (0.2) | 31.9 (0.4) | 31.5 (0.3) | 32.0 (0.4) | 32.0 (0.4) |
| N3 | 31.3 (0.4) | 31.1 (0.3) | 30.6 (0.4) | 31.1 (0.3) | 31.2 (0.4) | |
| UTM-RT | N1 | 31.8 (0.3) | 31.7 (0.4) | 31.9 (0.4) | 32.3 (0.2) | 31.7 (0.4) |
| N3 | 31.2 (0.4) | 31.2 (0.3) | 31.0 (0.4) | 31.4 (0.4) | 31.0 (0.2) | |
| ESwab | N1 | 31.7 (0.4) | 34.3 (1.1) | 34.8 (0.4) | 31.8 (0.3) | 33.5 (0.6) |
| N3 | 31.3 (0.3) | 33.7 (0.9) | 34.5 (0.4)d | 31.7 (0.4) | 33.8 (0.6)c | |
| M4 | N1 | 31.8 (0.2) | 32.1 (0.7) | 32.0 (0.5) | 31.0 (3.0) | 31.5 (0.2) |
| N3 | 31.3 (0.4) | 31.6 (0.7) | 31.1 (0.5) | 30.1 (3.0) | 31.0 (0.3) | |
| Saline | N1 | 29.2 (0.7) | 30.6 (0.5) | 31.4 (0.3) | 31.7 (0.4)c | 31.6 (0.9)c |
| N3 | 28.4 (0.6) | 29.6 (0.4) | 30.3 (0.3) | 30.6 (0.4)c | 30.7 (0.9)c | |
| BAL fluid | N1 | 31.8 (0.2) | 32.4 (0.6) | 32.2 (0.4) | 32.5 (0.3) | 32.5 (0.1) |
| N3 | 31.1 (0.2) | 31.3 (0.4) | 31.3 (0.3) | 31.8 (0.3) | 31.6 (0.2) | |
| Sputum | N1 | 31.4 (0.5) | 31.8 (1.0) | 31.6 (0.3) | 31.8 (0.5) | 31.8 (0.3) |
| N3 | 30.8 (0.6) | 30.9 (1.0) | 30.7 (0.1) | 30.8 (0.5) | 31.0 (0.4) | |
a
Testing was performed at QDID. Five replicates were assayed by rRT-PCR under the indicated conditions.
b
N1 and N3 TaqMan probes were as described in the Quest Diagnostics EUA package insert.
c
Increase of >2 CTs from day 0.
d
One of five replicates at day 5 did not yield detectable RNA for the N3 target.