Table 4.
Comparison of the 4-spot method with a 24-h urine collection (n = 26)
| Variable | 24 h urine collection (μg/day) | 24 h urine collection (ng/mg-Cr) | 4-spot (ng/mg-Cr) | Difference [95% confidence interval] | ICC |
|---|---|---|---|---|---|
| Estradiol | 0.77 (0.30, 1.90) | 1.73 (0.80, 3.26) | 1.68 (0.92, 3.81) | 0.16 [0.01, 0.31]* | 0.97 |
| Estrone | 6.0 (3.3, 9.9) | 13.7 (6.3, 19.2) | 14.4 (7.1, 18.8) | 0.8 [0.1, 1.4]* | 0.98 |
| 5α-pregnanediol | 34.9 (13.6, 88.4) | 71.4 (28.9, 257.2) | 60.9 (29.7, 242.0) | − 11.6 [− 38.7, 15.6] | 0.97 |
| 5β-pregnanediol | 99.2 (60.7, 214.0) | 243.9 (99.2, 408.9) | 204.3 (113.5, 466.6) | 44.0 [− 27.2, 115.2] | 0.96 |
Data presented as median (IQR)
Differences were calculated using a signed rank test (4-spot—24 h assay), as variables were not normally distributed. Note that ICCs were calculated between measurements expressed in identical units. Results for the 24-h collection are reported as ng/mg-Cr for ICC calculation and also as μg/day, the usual units for reporting results of 24-h collections
Cr creatinine, ICC intraclass correlation coefficient
* Estrone p = 0.03, estradiol p = 0.0499