ESPE Abstracts

Purpose: In the diagnosis of central precocious puberty (CPP), the gonadotropin-releasing hormone (GnRH) stimulation test using intravenously injected gonadorelin is the gold standard. However, gonadorelin is not always readily available. In this study, the diagnostic accuracy of a test based on the GnRH agonist triptorelin acetate (triptorelin) was compared to that of the classical gonadorelin-based test in the diagnosis of CPP in girls.

Methods: A retrospective chart review was performed to compare the clinical outcome of patients who underwent a GnRH stimulation test performed using intravenous gonadorelin (n= 74) vs. a subcutaneous triptorelin acetate test (triptorelin) test (n= 74). Among the 148 patients, 74 had CPP and 74 had precocious thelarche (PT). Luteinizing hormone (LH) and follicle-stimulating hormone levels were measured 0, 30, 60, 120, and 180 min after triptorelin injection, and 0, 30, 45, 60, and 90 min after gonadorelin injection. CPP was defined as a peak LH concentration ≥ 5.0 IU/L and PT as a peak LH concentration < 5.0 IU/L. The peak LH time detected by each method was compared, and the diagnostic value of the triptorelin test for CPP was determined in a receiver operating characteristic analysis.

Results: Peak LH after gonadorelin injection was measured at 30 min in 48% of patients, at 45 min in 47%, and at 60 min in 5.0%. After triptorelin injection, LH levels peaked at 30 min in 8%, at 60 min in 49%, at 120 min in 8.5%, and at 180 min in 35%. In the triptorelin test for the diagnosis of CPP, the peak LH cutoff value of 5.02 IU/L provided a sensitivity of 100% and a specificity of 100%.

Conclusion: The triptorelin test has a high diagnostic accuracy in the differential diagnosis of CPP vs. PT in girls, thus providing an effective alternative to the classic gonadorelin-based GnRH test. It should be noted that the peak LH concentration after triptorelin stimulation is likely to be reached later than after gonadorelin stimulation.