Table 1.
Intra-lab testing: repeatability, between-runs, within-days, and within-laboratory evaluations.
| Samples | Repeatability | Between Runs | Within Days | Within Lab | |||||
|---|---|---|---|---|---|---|---|---|---|
| SD | CV% | SD | CV% | SD | CV% | SD | CV% | ||
| Batch 1 | #1 (RI = 0.16) | <0.01 | 2.90 | 0.06 | 29.68 | 0.70 | 30.48 | 0.06 | 25.62 |
| #2 (RI = 0.16) | <0.01 | 4.19 | 0.08 | 36.32 | 0.07 | 27.67 | 0.06 | 28.94 | |
| #3 (RI = 1.30) | 0.03 | 10.69 | 0.12 | 8.57 | 0.16 | 11.48 | 0.13 | 9.52 | |
| #4 (RI = 1.50) | 0.02 | 5.74 | 0.11 | 7.35 | 0.16 | 10.03 | 0.25 | 14.69 | |
| #5 (RI = 2.17) | 0.02 | 3.02 | 0.13 | 5.81 | 0.10 | 4.23 | 0.25 | 10.59 | |
| #6 (RI = 4.46) | 0.07 | 6.60 | 0.02 | 0.50 | 0.18 | 3.88 | 0.57 | 12.17 | |
| Batch 2 | #1 (RI = 0.16) | <0.01 | 0.26 | 0.08 | 47.11 | 0.07 | 35.22 | 0.10 | 40.98 |
| #2 (RI = 0.16) | <0.01 | 2.51 | 0.07 | 41.51 | 0.07 | 37.35 | 0.10 | 41.73 | |
| #3 (RI = 1.30) | 0.01 | 2.41 | 0.05 | 3.99 | 0.05 | 3.89 | 0.06 | 5.40 | |
| #4 (RI = 1.50) | 0.02 | 5.01 | 0.21 | 13.69 | 0.27 | 16.04 | 0.29 | 15.55 | |
| #5 (RI = 2.17) | 0.03 | 4.97 | 0.42 | 19.59 | 0.42 | 18.29 | 0.44 | 17.61 | |
| #6 (RI = 4.46) | 0.08 | 7.86 | 0.89 | 22.44 | 1.03 | 23.07 | 0.83 | 17.82 | |
| Batch 3 | #1 (RI = 0.16) | <0.01 | 1.11 | 0.03 | 19.24 | 0.08 | 36.98 | 0.06 | 27.38 |
| #2 (RI = 0.16) | <0.01 | 1.94 | 0.02 | 12.23 | 0.06 | 28.24 | 0.06 | 25.61 | |
| #3 (RI = 1.30) | 0.01 | 5.37 | 0.17 | 12.93 | 0.15 | 11.47 | 0.12 | 9.49 | |
| #4 (RI = 1.50) | 0.02 | 6.55 | 0.42 | 23.93 | 0.36 | 19.14 | 0.34 | 18.17 | |
| #5 (RI = 2.17) | <0.01 | 0.11 | 0.39 | 16.86 | 0.36 | 14.69 | 0.37 | 15.92 | |
| #6 (RI = 4.46) | 0.01 | 0.62 | 0.85 | 18.70 | 0.92 | 18.75 | 0.75 | 15.41 | |
RI (reactivity index) calculated using the Anti-SARS-CoV-2 NCP IgG ELISA kit from Euroimmun Medizinische Labordiagnostika AG, Lübeck, Germany. SD (Standard deviation); CV% (Coefficient of variation). SARS-CoV-negative samples (#1 and #2); SARS-CoV-2-positive samples (#3 to #6).