The measurement of urinary gonadotropins for assessment and management of pubertal disorder

OBJECTIVE: Measurement of urinary LH (uLH) and FSH (uFSH) may facilitate non-invasive pubertal assessment but there is a need for further validation by studying children and adolescents with disorders of puberty. DESIGN: 65 cases (Male: 25) with a median age of 12 years (2.9-18.1) supplied at least one non-timed urine sample for uLH and uFSH measurement by immunoassay and corrected for creatinine excretion. 25 cases were receiving GnRH-agonist (GnRH-a) at the time of sample collection. In 41 cases, urine samples were collected prior to a LH RH test and in 12 cases matched serum samples for basal LH (sLH) and FSH (sFSH) were also available. RESULTS: There was a significant correlation between sLH and uLH: uCr (r=0.82; p-value <0.001) and sFSH and uFSH: uCr (r=0.93; p-value <0.001). Based on receiver operator characteristics analysis, a uLH : uCr value of 0.05 IU/mmol as a cut-off would detect a LH peak >5U I/L with a sensitivity of 86% and a specificity of 72% with a positive predictive value of 93%. In pubertal boys (6) and girls (22) with a sLH peak >5UI/L, median uLH: uCr was 0.27 IU/mmol (0.27-0.28) and 0.17 IU/mmol (0.09-0.43), respectively. The median uFSH: uCr was 0.51 IU/mmol (0.41-0.60) for boys and 1.1 IU/mmol (0.21-2.44) for girls. In the 25 cases on GnRH-a, the median uLH : uCr for boys and girls was 0.02 IU/mmol (0.01-0.02) and 0.02 IU/mmol (0.004-0.07), respectively, and the median uFSH: uCr was 0.07 IU/mmol (0.05-0.09) and 0.27 IU/mmol (0.09-0.54), respectively. CONCLUSION: Urinary gonadotrophins reflect serum gonadotrophin concentration and may represent a reliable non-invasive method of assessing pubertal progress.