SUN-265 Performance of Basal and GnRH Analog-Stimulated LH Levels Assessed by an Electrochemiluminescence Assay in Girls with Central Precocious Puberty

• Published in: Journal of the Endocrine Society 2019-04, Vol.3 (Supplement_1)
• Main Authors: Faria, Aline, Canton, Ana, Brito, Luciana, Palhares, Heloisa, Seraphim, Carlos, Resende, Elisabete Mantovani, Borges, Maria de Fatima, Latronico, Ana Claudia, Mendonca, Berenice, Brito, Vinicius
• Format: Article
• Language: English
• Subjects: Pediatric Endocrinology
• ISSN: 2472-1972; 2472-1972
• DOI: 10.1210/js.2019-SUN-265

Background: The laboratory evaluation of patients with precocious puberty is useful to differentiate central precocious puberty (CPP) from isolated thelarche (IPT) and peripheral precocious puberty (PPP). Ultrasensitive immunoassays, such as electrochemiluminescence (ECLIA), improved sensitivity and specificity of basal and GnRH-stimulated LH levels to establish the differential diagnosis among these conditions. Aim: To establish the diagnostic value of basal and GnRHa-stimulated LH values and basal estradiol assessed by ECLIA in pubertal disorders. Patients and Methods: We included 38 girls with pubertal disorders (28 CPP, 8 IPT, and 2 PPP). Their medical records were systematically revised. Clinical and hormonal data [basal and GnRH analog -stimulated LH levels (2 hs after leuprorrelin 3.75 mg) and basal estradiol] were analyzed. Gonadotropins and estradiol levels were assessed by ECLIA (Roche, Cobas e 6000). The functional sensitivity of the assays was 0.15 IU/L for LH, FSH 0.6 IU/L for FSH and 17 pg/mL for estradiol. Basal gonadotropins and estradiol were also assessed in a control group composed by 16 prepubertal and 19 pubertal girls. The cutoff values for basal and GnRH analog- stimulated LH for diagnosis of CPP was set at < 0.3 IU/L and 8 IU/L, respectively (1). Results: The mean age of girl with CPP, IPT, and PPP at the first clinical visit was 8 ± 0.9yr (5.25- 9.6 yr), 4.25± 2.6 (0.7-7.8 yr), and 5.12±2.9 (3.1 -7.1 yr), respectively. All CPP girls presented breast development ranging from B2 to B5, whereas IPT group B2-B4 and PPP group (B2). Pubarche was presented in 86% of girls with CPP (PH 2- PH 5). Only one girl in IPT group also presented pubarche (PH3), associated to zinc oxide cream use and none in PPP group presented pubarche. The mean basal LH was 3.4 ± 1.6 (