Accuracy of Endocrine Tests for Detecting Hypogonadotropic Hypogonadism in Girls

ObjectiveTo assess the accuracy of inhibin B and the gonadotropin releasing hormone agonist test for the diagnosis of hypogonadotropic hypogonadism (HH).Study designWe performed a retrospective analysis of data collected 2009-2014 using a strict clinical protocol. All prepubertal nonunderweight girls, aged 13-17.5 years with Tanner breast stage B1/B2 and low estradiol levels, were tested and re-examined at 6-month intervals (n = 21). Constitutional delay of growth and puberty was defined by spontaneous menarche; HH was identified by association with specific causes of HH or no spontaneous progress of puberty during follow-up. Inhibin B was measured using enzyme-linked immunosorbent assay, and follicle-stimulating hormone and luteinizing hormone (basal and stimulated by triptorelin) were measured using a chemiluminescence immunoassay.ResultsThe cohort comprised 12 girls with constitutional delay of growth and puberty and 9 girls with HH. The causes of HH included hypopituitarism (n = 3), Prader-Willi syndrome, chromosomal aberration, intellectual disability syndrome with ataxia, and idiopathic causes (n = 2). Each measurement, basal inhibin B <20 pg/mL or stimulated follicle-stimulating hormone (4 hours) <11 IU/L, demonstrated a sensitivity and a specificity of 100% for the detection of HH. Stimulated luteinizing hormone (4 hours) <9 IU/L showed 100% sensitivity but only 83% specificity.ConclusionsInhibin B seems to be the ideal measurement for detecting HH in girls. The gonadotropin releasing hormone agonist test is an alternative diagnostic modality, although this approach is more invasive and laborious.