Researchers tested a skin‑injected hormone called triptorelin to see if it can replace the usual IV test for spotting early puberty in girls. They found that measuring a hormone (LH) 2 hours after the injection works well, but this is a medical diagnostic tool for children, not something useful for health‑optimizing adults.

The gold standard gonadotropin-releasing hormone (GnRH) stimulation test uses the response to intravenously injected gonadorelin to diagnose central precocious puberty (CPP). However, gonadorelin is not always readily available. This study investigated the diagnostic efficacy of the subcutaneous triptorelin test and the optimal blood sampling time for diagnosis of CPP. This study retrospectively examined the medical records of 220 girls who had undergone either the triptorelin or gonadorelin test and compared their clinical characteristics. We retrospectively compared clinical parameters between girls diagnosed with CPP (<i>n</i> = 111) and idiopathic premature thelarche (IPT) (<i>n</i> = 109) using three different diagnostic methods: the gonadorelin, triptorelin 120 min, and triptorelin 180 min tests. The diagnostic ability of the stimulated luteinizing hormone (LH) concentration in the triptorelin test for CPP was evaluated using receiver operating characteristic (ROC) analysis. The CPP group exhibited higher basal and peak gonadotropin levels, more advanced bone age, and a lower body mass index standard deviation score than the IPT group. In the gonadorelin test group, all girls with CPP exhibited a peak LH response 30-60 min after intravenous gonadorelin injection. In the triptorelin test group, most girls with CPP exhibited a peak LH response 60-180 min after subcutaneous triptorelin injection (<i>n</i> = 68). On the ROC curve, a peak LH concentration of &#x2265; 4.52 IU/L at 120 min had the highest CPP diagnostic accuracy, with sensitivity and specificity of 100% and 95.83%, respectively.