Table 2.
Intra-and inter-run precision and accuracy of cortisol assay.
|
Nominal level (ng/ml) |
Intra-day (n=10) | Inter-day (n=20) | ||||
|---|---|---|---|---|---|---|
|
Mean (SD) measured level |
CV (%) |
Bias (%) |
Mean (SD) measured level |
CV (%) |
Bias (%) |
|
| 0.5 | 0.52 (0.05) | 9.0 | 3.2 | 0.51 (0.04) | 8.4 | 2.2 |
| 1.5 | 1.42 (0.09) | 6.0 | -5.5 | 1.47 (0.11) | 7.7 | -2.0 |
| 50 | 52.77 (1.49) | 2.8 | 5.1 | 53.27 (2.61) | 4.9 | 6.5 |
| 90 | 100.79 (2.38) | 2.4 | 12.0 | 99.23 (3.86) | 3.9 | 10.3 |
SD: standard deviation. CV: coefficient of variation = standard deviation divided by mean measured concentration x 100. Bias = measured level - nominal level divided by nominal level x 100.