Table 3.
Ct values of contrived clinical specimen spiked with different concentrations of SARS-CoV-2 RNA.
| Sample ID (SARS-CoV-2 RNA Copies) | Modified CDC SARS-CoV-2 assay Ct Values |
Interpretation | ||
|---|---|---|---|---|
| Target N1 | Target N2 | Target RP | ||
| 001−020 (200−400) | 32.75 ± 2.14* | 32.12 ± 2.23* | 23.44 ± 3.24* | Detected |
| 021 (60,000) | 25.15 | 24.81 | 22.58 | Detected |
| 022 (30,000) | 28.17 | 26.17 | 21.61 | Detected |
| 023 (15,000) | 26.84 | 27.46 | 21.58 | Detected |
| 024 (7500) | 28.37 | 28.5 | 21.62 | Detected |
| 025 (3750) | 29.33 | 29.75 | 21.7 | Detected |
| 026 (1875) | 30.23 | 31.02 | 21.54 | Detected |
| 027 (937) | 31.13 | 31.97 | 21.38 | Detected |
| 028 (468) | 32.59 | 32.66 | 21.59 | Detected |
| 029 (300) | 32.55 | 32.66 | 21.59 | Detected |
| 030 (234) | 32.85 | 34.41 | 21.63 | Detected |
| 031- 060 (negative) | ND | ND | 20.9 ± 0.5 | Not Detected |
*
Average Ct values and standard deviation of the mean for samples 1–19 spiked with 200–400 copies of SARS-CoV-2 RNA and 1 known positive patient sample; ND: No Ct value detected.