Objectives: Urinary hormone concentrations are often adjusted to correct for hydration status. We aimed to determine whether first morning void urine hormones in growing adolescents require adjustments and, if so, whether urinary creatinine or specific gravity (SG) are better adjustments. Design and Methods: The study population was adolescents aged 10.1 to 14.3 years initially who provided fasting morning blood samples at 0 and 12 months (n=343) and first morning urine every three months (n=644). Unadjusted, creatinine and SG-adjusted hormonal concentrations were compared by Deming regression and Bland-Altman analysis and grouped according to self-rated Tanner stage or chronological age. F-ratios for self-rated Tanner stages and age groups were used to compare unadjusted and adjusted hormonal changes in growing young adolescents. Correlations of paired serum and urinary hormonal concentration of unadjusted and creatinine and SG adjusted were also compared. Results: Fasting first morning void hormone concentrations correlated well and were unbiased between unadjusted or adjusted by either creatinine or SG. Urine creatinine concentration increases with Tanner stages, age and male gender whereas, urine SG was not influenced by Tanner stage, age or gender. Adjustment by creatinine or SG of urinary luteinizing hormone, estradiol, testosterone, dihydrotestosterone and dehydroepiandrosterone concentrations did not improve correlation with paired serum concentrations. Conclusions: Urine steroid and LH concentrations in first morning void samples of adolescents are not significantly influenced by hydration status and may not require adjustments; however, if desired, both creatinine and SG adjustments are equally suitable
