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Inhibin B plus LH vs Gn RH agonist test for distinguishing constitutional delay of growth and puberty from isolated hypogonadotropic hypogonadism in boys
Author(s) -
Binder Gerhard,
Schweizer Roland,
Blumenstock Gunnar,
Braun Regina
Publication year - 2015
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12613
Subject(s) - medicine , endocrinology , hypogonadotropic hypogonadism , triptorelin , delayed puberty , basal (medicine) , agonist , gonadotropin , gonadotropin releasing hormone , luteinizing hormone , hormone , receptor , insulin
Summary Objective The distinction between constitutional delay of growth and puberty ( CDGP ) and isolated hypogonadotropic hypogonadism ( IHH ) in males with delayed puberty is difficult but important for timely treatment. We assessed the accuracy of the G n RH agonist test (triptorelin 0·1 mg) in comparison with inhibin B alone or in combination with basal LH for the diagnosis of IHH . Patients and measurements Ninety‐seven prepubertal males aged 13·7–17·5 year, with testicular volumes ≤4 ml, were examined every 6 months. CDGP was defined by a testicular volume ≥8 ml after 18 months, and IHH was defined by a testicular volume <5 ml after 24 months follow‐up. Inhibin B concentrations were measured by ELISA , and LH concentrations were measured by CLIA . Results At follow‐up, the cohort comprised 52 boys with CDGP and nine with IHH. The other patients were lost for follow‐up ( n = 10), had not reached follow‐up yet ( n = 20) or did not reach a definite testicular volume ( n = 6). Basal LH <0·3 IU/l, stimulated LH (4 h) <5·3 IU/l or inhibin B <111 pg/ml had 100% sensitivity for IHH. Only LH (4 h) <5·3 IU/l had a specificity of 100%, and the specificities of basal LH <0·3 IU/l (88%) or inhibin B <110 pg/ml (92%) were lower. The combination of LH <0·3 IU/l with inhibin B <111 pg/ml increased the specificity to 98·1%. Conclusions The LH response 4 h after G n RH agonist stimulation has an excellent accuracy for the diagnosis of IHH in prepubertal boys with delayed puberty. However, the measurement of inhibin B and basal LH in combination is a valid, reliable and less‐invasive alternative test.