Table 2.
Evaluation of the limit of detection (LOD) for the three processing methods using serially diluted NPS and saliva specimens from a COVID-19 patient.
| NPS Sample | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Sample Dilution | PKH |
Heat Only |
Direct |
||||||
| Test 1 | Test 2 | Test 3 | Test 1 | Test 2 | Test 3 | Test 1 | Test 2 | Test 3 | |
| 1:10 | 35.65 | 35.37 | 35.16 | 36.74 | 36.65 | 36.57 | 38.18 | 36.42 | 40.00 |
| 1:100 | 38.98 | 37.23 | 38.03 | – | – | – | 40.00 | 40.00 | 38.30 |
| 1:1000 | 37.77 | 40.00 | 40.00 | – | – | – | – | – | – |
| 1:10000 | – | – | – | – | – | – | – | – | – |
| 1:100000 | – | – | – | – | – | – | – | – | – |
| Saliva Sample | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Sample Dilution | PKH |
Heat Only |
Direct |
||||||
| Test 1 | Test 2 | Test 3 | Test 1 | Test 2 | Test 3 | Test 1 | Test 2 | Test 3 | |
| 1:10 | 31.81 | 32.20 | 32.27 | 35.29 | 35.05 | 34.88 | 33.11 | 32.85 | 31.88 |
| 1:100 | 36.13 | 36.91 | 36.75 | 38.46 | 40.00 | 40.00 | 37.79 | 36.09 | 35.78 |
| 1:1000 | 39.10 | 38.84 | 39.59 | – | – | – | 40.00 | 38.02 | 38.30 |
| 1:10000 | 40.00 | 40.00 | 40.00 | – | – | – | – | – | 40.00 |
| 1:100000 | – | – | – | – | – | – | – | – | – |
Data represent Ct values. The Ct values for the total nucleic acid of the undiluted NPS and saliva specimen extracted using NucliSENS easyMAG extraction system is 21.59 and 21.14, respectively.