目的：探讨卵泡刺激素（FSH）、黄体生成素（LH）、LH/FSH比值在辅助鉴别诊断女童性早熟中的临床价值。方法：220例假性性早熟和61例真性性早熟女童均进行促性腺激素释放激素（GnRH）兴奋试验。统计实验前和实验后30 min、60 min FSH、LH检测结果并计算LH/FSH比值。ROC曲线分析FSH、LH、LH/FSH比值用于诊断性早熟的敏感度并确定最佳诊断截点。结果：通过LH、LH/FSH比值判别性早熟ROC曲线下面积为0.90和0.95。LH峰值截点为10.15 IU/L，敏感度、特异性分别为0.92和0.89；LH/FSH比值截点为0.60，漏诊率为6.0%，特异性为0.91。若患者检测结果满足LH峰值＞10.15 TU/L、LH/FSH比值＞0.60两个条件中任何一个即诊断为真性性早熟，则敏感度、特异性分别为0.97、0.94；若两个条件同时满足才诊断为真性性早熟，则特异性为1.00，敏感度为0.85。结论：LH峰值＞10.15 IU/L且LH/FSH比值＞0.60时，可鉴别诊断为真性性早熟，若两个条件中仅一者满足，为防止漏诊或误诊，应进一步随访观察，以明确诊断。

OBJECTIVE: To study the value of follicle stimulating hormone (FSH), luteinizing hormone (LH) and LH/FSH ratio in the diagnosis of precocious puberty in girls by ROC curve analysis. METHODS: Gonadotropin-releasing hormone (GnRH) stimulation test was performed on 220 girls with pseudo-sexual precocity and 61 girls with true sexual precocity. Blood LH and FSH levels were measured before and after 30 and 60 minutes of taking the GnRH test. The ratio of LH to FSH was calculated. Sensitivity and best point for the diagnosis of precocity according to LH, FSH and LH/FSH ratio were analyzed by ROC curve analysis. RESULTS: The area under the ROC curve was 0.90 and 0.95 according to LH level and LH/FSH ratio respectively for the diagnosis of precocity. The best point for diagnosis by LH was 10.15 IU/L, with a sensitivity of 0.92 and specificity of 0.89. The best point for diagnosis by LH/FSH ratio was 0.60, with a missed diagnosis rate of 6.0% and specificity of 0.91. When true sexual precocity was diagnosed based on one index between LH>10.15 IU/L and LH/FSH ratio>0.60, sensitivity was 0.97 and specificity was 0.94. When the diagnosis of true sexual precocity was diagnosed based on both LH>10.15 IU/L and LH/FSH>0.60, sensitivity was 0.85 and specificity was 1.00. CONCLUSIONS: True sexual precocity can be diagnosed when both LH>10.15 IU/L and LH/FSH ratio>0.60. Only one of the two indexes for the diagnosis of true sexual precocity is presented, further observation is necessary to decrease missed diagnosis and misdiagnosis.