Usefulness of a basal LH level to diagnose Central Precocious Puberty (CPP) in girls.

FREIRE, ANALÍA; ARCARI, ANDREA; BALLERINI, MARÍA GABRIELA; ESCOBAR, MARÍA EUGENIA;; BERGADÁ, IGNACIO; GRYNGARTEN, MIRTA; ROPELATO, MARÍA GABRIELA

Milan

Congreso; 9th Joint Meeting of Pediatric Endocrinology; 2013

ENDO, SLEP

Page 178/9 Abstr P1 d3 563 Background: The diagnosis of CPP in girls requires gonadotropin. stimulation test 10 confirm the hypothalamic-pituitary-ovarian axis activation. However,new and more sensitive immunoassays could be useful to aehieve an acceptable diagnostie efficiency by means of basal serum gonadotropins levels. Objectíve: To determine the usefulness of basal serum gonadotropins in the diagnosis of Cl'P in girls, using an electrochemiluminescense assay (EeLlA). Methods: A cohort of 142 girls who presented breast development before 8 years of age who underwent GnRH stimulation test were inciuded. Diagnosis of Cl'P was made on the basis of clinical criteria and a peak LH >6 ¡U/L. CPP girls with previous central nervous system condition or pathologic MRl were classified as ncurogenic CPP (Nepp), the others were considered as idiopathic epp (le?p). ;?-Girls who had lower peak LH values and showed no pubertal progression throughout follow-up for at least one year after the test were considered as premature thelarche (PT). Basal gonadotropins were analyzed by ROC curves to determine the best cut-off to differentiate CPP vs PT and their positive predictive value (PPV) and negative predictive value (NPV). ResuIts: 105 girls were c1assified as CPP (72 ICPP, 33 NCPP) and 37 as PT. ROC curves showed that a cut-offvalue ofbasal LH= 0.3 IUIL, setting the specificity (E) at 100%, had 64.42% of Sensitivity (S) in the whole group for the diagnosis ofCPP, withaPPVof 100% and NPVof50%. A basal LH value >0.3 IUIL identified 38/72 ICPP girls (S:52.8%) but identified 30/32 NCPP girls (S:94%, NPV:95%). Basal FSH >4.2 IUIL setting E at 100% showed S of 45% in the whole group. Conclusions: Basal LH >0.3 IUIL using ECLIA is adequate to confirm CPP, however lower values are not definite to refute the diagnosis of CPP. Basal FSH does not improve diagnosis sensitivity. But in patients suspected of having NCPP, the basal LH value has high diagnostic accuracy for diagnosing CPP without requiring a further test.