ABSTRACT Objective To determine whether first-voided urinary LH (FV-ULH) - level measurement can adequately assess pubertal suppression as much as standard tests can. Subjects and methods The study group included patients with central precocious puberty and rapidly progressing early puberty who received up to 3 - 4 doses of GnRHa therapy monthly and did not have adequate hormonal suppression after GnRH stimulation (90-minute LH level > 4 IU/L).

Design:

All of the participants underwent an LHRH test just after admission to the study. According to the stimulated peak LH levels, the patients were divided into 2 groups and followed until the end of the first year of treatment. The concordance between FV-ULH and stimulated LH levels was assessed. Results The FV-ULH levels in patients with inadequate hormonal suppression were significantly high compared to patients with adequate hormonal suppression. FV-ULH levels were very strongly correlated with stimulated LH levels (r = 0.91). Its correlation with basal LH levels was significant (r = 0.65). However, this positive correlation was modestly weakened after the first year of treatment. The cutoff value for FV-ULH of 1.01 mIU/mL had the highest sensitivity (92.3%) and specificity (100%). Conclusion FV-ULH levels, using more reliable and sensitive assay methods, can be used to monitor the adequacy of GnRHa therapy.