ESPE Abstracts

Introduction: Early morning basal serum luteinizing hormone LH) (S-LH) ≥ 0.3 IU/L is a specific marker for the onset of central puberty. In this study, we aimed to investigate the sensitivity and specificity of the first-morning-voided (FMV) total urinary LH (U-LH) to replace this marker.

Methods: We re-analyzed our previously published data set of 297 children (145 boys and 152 girls, aged 5-15 years, across Tanner stages 1 through 5) using ROC analysis and determined cutoff values for FMV total U-LH in predicting early morning S-LH concentration at or above 0.3 IU/L. We also determined S-LH and S-FSH concentrations in girls at different stages of sexual maturation.

Results: ROC analysis showed that specific FMV total U-LH cutoff levels in girls and boys predicted early morning S-LH levels of 0.3 IU/L or higher with 97.4% sensitivity and 90.6% specificity. Higher cutoff levels for U-LH yielded 94.7% specificity at the expense of a relatively lower level of sensitivity (94.1%). The areas under the curve were 0.98 in boys and 0.99 in girls, respectively. Additionally, the increase in FMV total U-LH (or S-LH) levels identified the activation of central pubertal development at the mean age of 10.3 (10.3) in boys and 10.5 (10.6) in girls. The S-FSH concentrations of the six biochemically prepubertal girls with thelarche were significantly higher than those measured in biochemically and clinically prepubertal girls of the same 10-12-year-old age group and significantly lower than those measured in both biochemically and clinically pubertal girls (P = .039 and P = .018, respectively).

Conclusion: FMV total U-LH concentrations reliably reflect pubertal morning serum LH levels and are effective in detecting the onset of central puberty, which occurs at similar ages in both sexes. Concurrent S-FSH or noninvasive FMV U-FSH determinations may be useful in the differential diagnosis of isolated thelarche.