Predictive value of serum gonadotropins measured by ultrasensitive methods in boys with nonpalpable gonads.

GRINSPON R; BEDECARRÁS P; ROPELATO MG; REY R.; GOTTLIEB S.

Boston, USA,

Congreso; Endocrine Society 88th Annual Meeting.; 2006

Endocrine Society

Predictive value of serum gonadotropins measured by ultrasensitive methods in boys with nonpalpable gonads. Romina GRINSPON, María Gabriela ROPELATO, Patricia BEDECARRAS, Silvia GOTTLIEB, Rodolfo REY Centro de Investigaciones Endocrinológicas (CEDIE) and División de Endocrinología Hospital de Niños “Ricardo Gutiérrez”, Buenos Aires, Argentina In normally virilized boys with non palpable gonads, the assessment of the presence and functional capacity of the testes is essential. Little attention is often given to the circulating levels of LH and FSH, mainly during the quiescent period of the hypothalamic-pituitary axis. Sertoli cell markers, e.g. anti-Müllerian hormone (AMH) and inhibin B are sensitive and specific. However, assays for these hormones may not always be available. The aim of this study was to determine the value of basal serum gonadotropin levels, measured using ultrasensitive methods, to assess the existence and integrity of testicular tissue. We evaluated the levels of FSH and LH (IFMA), AMH (ELISA), and T (RIA) in samples of 6 boys 0-6 month-old, 43 prepubertal (>6 months-old) and 11 pubertal, with normal virilization but nonpalpable testes. Clinical charts of all patients included were thoroughly reviewed. Absence of functional testicular tissue was diagnosed when AMH was non detectable and T was not >50 ng/dL (post-hCG or basally in patients with elevated LH). Results of sensitivity, specificity and predictive values of normal or elevated gonadotropin levels are shown in tables 1 and 2. Conclusions: Normal FSH reliably rules out anorchia in most cases. Normal LH is less predictive. Although often observed in patients with hypofunctional testes, elevated LH is highly associated with anorchia in prepubertal boys. FSH levels > 10 or < 2 IU/L are highly predictive of anorchia or of present testes respectively, but intermediate levels (2-10 IU/L) do not efficiently discriminate between anorchia and abnormal testes. Table 1. Predictive values (PV) of serum gonadotropins for the assessment of anorchia in patients with nonpalpable gonads. High LH High FSH Positive PV (%) Negative PV (%) Positive PV (%) Negative PV (%) 0-6 months 80.0 100.0 80.0 100.0 Prepubertal 72.7 50.0 64.7 96.2 Pubertal 75.0 66.7 77.8 100.0 Reference levels: LH: 0-6 mo. < 5 IU/L; Prepubertal < 0.3 IU/L; Pubertal < 6 IU/L. FSH: 0-6 mo. < 2.5 IU/L; Prepubertal < 2 IU/L; Pubertal < 7.9 IU/L. Table 2. Sensitivity, specificity and positive predictive value (PV) of serum FSH for anorchia or hormonally normal or abnormal testes in prepubertal boys FSH Sensitivity (%) Specificity (%) Positive PV (%) > 10 IU/L (anorchia) 66.7 93.5 80.0 2-10 IU/L (abnormal testes) 18.2 85.7 57.1 < 2 IU/L (normal testes) 100.0 50.0 34.6