The role of urinary LH and FSH in the diagnosis of pubertal disorders

Background: Various hormonal parameters used to differentiate between different causes of pubertal disorders are invasive, cumbersome, and has variable sensitivity and specificity. Thus, the use of a noninvasive test like urinary gonadotropin for the diagnosis of pubertal disorders will offer a significant advantage. Objective: To study the role of urinary gonadotropins (uLH, uFSH) for the diagnosis of various pubertal disorders and in the monitoring of Gonadotrophin releasing hormone, Hypothalamic-pituitary-gonadal (GnRHa) therapy in patients with central precocious puberty (CPP). Materials and Methods: We evaluated 35 healthy children and 96 patients with disorders of puberty out of which 31 cases had early puberty and 65 cases had delayed puberty. We used Spearman's correlation coefficient to evaluate the correlation between the serum and urinary gonadotropins. We used Mann-Whitney U test (for 2 groups) and Kruskal-Wallis test (for > 2 groups) to compare the median urinary and serum gonadotropins of different groups. Results: The urinary gonadotropins correlated strongly with serum gonadotropins in both healthy controls and individuals with pubertal disorders. The uLH level of ≥0.76 IU/L had 100% sensitivity and specificity to differentiate CPP from peripheral precocious puberty, whereas uLH level of ≥1.07 IU/L had 100% sensitivity and specificity for differentiating CPP from PT. In patients with delayed puberty, uFSH of ≥20.51 IU/L had 94.7% sensitivity and 91.3% specificity for the diagnosis of Hyper-Hypo cases and uLH level of ≥0.5 IU/L had sensitivity of 96.2% and specificity of 85% to differentiate constitutional delay in growth and puberty from hypogonadotropic-hypogonadism. In CPP patients on GnRHa therapy, the uLH level of ≥0.13 IU/L had 100% sensitivity and 86.7% specificity to identify those who had nonsuppressed serum LH levels. Conclusion: The urinary gonadotropins can be used as a reliable noninvasive test for the diagnosis of various pubertal disorders and also for monitoring of CPP patients on GnRHa therapy.