Objective: To assess the diagnostic value of the simplified gonadorelin stimulation test for precocious puberty.
Methods: Two hundred and ninety-two girls with signs of advanced breast development received the gonadorelin stimulation test. According to the result of gonadorelin stimulation test, the girls were divided into 3 groups: 151 with central precocious puberty (CPP),119 with premature thelarche (PT) and 22 with peripheral precocious puberty (PPP).
Results: LH or FSH levels at 15 min, 30 min, 60 min in PPP group were not significantly different (P>0.05). Those were significantly different in PT group (P<0.01). The highest levels of LH were at 30 min and the highest levels of FSH were at 60 min. LH or FSH levels at 15 min, 30 min, 60 min in CPP group were significantly different (P<0.01) with the highest levels at 30 min. The ratio of basal LH and FSH >0.2 had a diagnostic sensitivity of 48.3 % and specificity of 69.7%. Taking the LH/FSH ratio >0.9 at 15 min, 30 min, 60 min as cut-off value, the diagnostic sensitivity was 80.1%, 68.9% and 38.4%, and the specificity was 90.8%, 96.6% and 69.7%, respectively.
Conclusion: The LH/FSH ratio>0.9 at 15 min after gonadorelin stimulation test can be used as a cut-off value to differentiate CPP from PT and blood sample at 60 min were not necessary.