GnRH and HCG tests are both necessary in differential diagnosis of male delayed puberty
L. Dunkel, J. Perheentupa, M. Virtanen and J. Maenpaa
The discriminative power of the gonadotropin releasing hormone test and the
human chorionic gonadotropin (HCG) test in the diagnosis of gonadotropin
deficiency was studied in 73 boys referred because of delayed pubertal
development or suspicion of gonadotropin deficiency. Hypogonadotropic
hypogonadism was confirmed by clinical follow-up in 21 of the boys and
excluded in the others because of normal pubertal development. Those latter
boys served as a reference group. The post-HCG serum testosterone level was
subnormal in hypogonadotropic hypogonadism on 12 of 19 occasions (in the
reference group on two of 46 occasions) and the post-gonadotropin releasing
hormone serum luteinizing hormone level was subnormal on fourteen of 22
occasions (zero of 65). Four of the seven boys with hypogonadotropic
hypogonadism who had normal post-HCG testosterone levels had subnormal peak
luteinizing hormone levels. Of the remaining three boys, two had low basal
testosterone levels. Combining the two tests therefore improved the
diagnostic accuracy.
