Gestational age (weeks) | Cortisol (nmol/l) |
24 | 110–744 |
25 | 100–671 |
26 | 90–605 |
27 | 81–545 |
28 | 73–491 |
29 | 66–443 |
Based on the regression equation (log(cortisol) = 3.5373 − 0.045 × GA) and the residual standard deviation (0.207098) about the regression line, a reference range for each week of GA is given by the points determined by mean ±2 residual standard deviations on the logarithmic scale, which were transformed back to the original units.