page_title: Delayed puberty
section_title: Laboratory evaluation
hierarchical_section_title: Delayed puberty / Diagnosis / Laboratory evaluation
caption_attribution_description: English: Workup for delayed puberty
context_page_description: Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormonal signs that puberty has begun. In the United States, girls are considered to have delayed puberty if they lack breast development by age 13 or have not started menstruating by age 16. Boys are considered to have delayed puberty if they lack enlargement of the testicles by age 14. Delayed puberty affects about 2% of adolescents.
  Most commonly, puberty may be delayed for several years and still occur normally, in which case it is considered constitutional delay of growth and puberty, a common variation of healthy physical development. Delay of puberty may also occur due to various causes such as malnutrition, various systemic diseases, or defects of the reproductive system or the body's responsiveness to sex hormones.
  Initial workup for delayed puberty not due to a chronic condition involves measuring serum FSH, LH, testosterone/estradiol, as well as bone age radiography.
context_section_description: The first step in evaluating children with delayed puberty involves differentiating between the different causes of delayed puberty. Constitutional delay can be evaluated with a thorough history, physical, and bone age. Malnutrition and chronic diseases can be diagnosed through history and disease-specific testing. Screening studies include a complete blood count, an erythrocyte sedimentation rate, and thyroid studies. Hypogonadism can be differentiated between hyper- and hypo-gonadotropic hypogonadism by measuring serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) (gonadotropins to measure pituitary output), and estradiol in girls (to measure gonadal output). By the age of 10-12, children with failure of the ovaries or testes will have high LH and FSH because the brain is attempting to jump-start puberty, but the gonads are not responsive to these signals.
  Stimulating the body by administering an artificial version of gonadotropin-releasing hormone (GnRH, the hypothalamic hormone) can differentiate between constitutional delay of puberty and a GnRH deficiency in boys, although no studies have been done in girls to prove this. It is often sufficient to simply measure the baseline gonadotrophin levels to differentiate between the two. 
  In girls with hypogonadotropic hypogonadism, a serum prolactin level is measured to identify if they have the pituitary tumor prolactinoma. High levels of prolactin would warrant further testing with MRI imaging, except if drugs inducing the production of prolactin can be identified. If the child has any neurological symptoms, it is highly recommended that the physician obtains a head MRI to detect possible brain lesions. 
  In girls with hypergonadotropic hypogonadism, a karyotype can identify chromosomal abnormalities, the most common of which is Turner syndrome. In boys, a karyotype is indicated if the child may have a congenital gonadal defect such as Klinefelter syndrome. In children with a normal karyotype, defects in the synthesis of the adrenal steroid sex hormones can be identified by measuring 17-hydroxylase, an important enzyme involved in the production of sex hormones.
caption: Workup for delayed puberty.
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