Unfortunately, in the absence of hyposmia, anosmia, a tumour or a midline defect, it is virtually impossible to separate a patient with isolated gonadotrophin deficiency from one with constitutional delay in growth. Patients with primary gonadal failure, however, will be easily diagnosed due to the elevation of gonadotrophin concentrations. The GnRH test may be useful in the diagnosis of subtle cases of gonadotrophin excess in primary gonadal failure and in the determination of endocrine onset of puberty in a patient with constitutional delay who is on the verge of physical development.
