GnRH Stimulation Test in Precocious Puberty: Single Sample is Adequate for Diagnosis and Dose Adjustment

OBJECTIVE Gonadotropin stimulation test is the gold standard to document precocious puberty. However, the test is costly, time-consuming and uncomfortable. The aim of this study was to simplify the intravenous gonadotropin-releasing hormone (GnRH) stimulation test in the diagnosis of precocious puberty and in the assessment of pubertal suppression. METHODS Data pertaining to 584 GnRH stimulation tests (314 tests for diagnosis and 270 for assessment of pubertal suppression) were analyzed. RESULTS Forty-minute post-injection samples had the greatest frequency of "peaking luteinizing hormone (LH)" (p<0.001) in the diagnostic tests when the cut-off value was taken as 5 IU/L for LH, 40th minute sample was found to have 98% sensitivity and 100% specificity in the diagnosis of precocious puberty, while the sensitivity and specificity of the 20th minute sample was 100% in the assessment of pubertal suppression. CONCLUSION LH level at the 40th minute post-injection in the diagnosis of central precocious puberty and at the 20th minute post-injection in the assessment of pubertal suppression is highly sensitive and specific. A single sample at these time points can be used in the diagnosis of early puberty and in the assessment of pubertal suppression.