From the Guidelines
Before initiating gonadotropin-releasing hormone (GnRH) agonists in an adolescent, baseline hormone levels including FSH, LH, and estradiol should be obtained as clinically indicated by accelerated pubertal progression and growth. When considering the use of GnRH agonists, also known as puberty blockers, in adolescents, it is crucial to prioritize their safety and well-being by conducting appropriate laboratory tests. These tests are essential for establishing baseline values to monitor for potential side effects of GnRH agonists. According to the study published in the Journal of Clinical Oncology 1, laboratory tests such as FSH, LH, and estradiol are recommended as clinically indicated by accelerated pubertal progression and growth. Additionally, a comprehensive approach to care should include regular follow-up labs every 3-6 months to monitor hormone suppression and metabolic parameters, as well as annual bone density reassessments to monitor the potential effects of puberty suppression on bone mineralization 1. Some key laboratory tests to consider include:
- Baseline hormone levels (FSH, LH, estradiol or testosterone depending on the adolescent's sex assigned at birth)
- Comprehensive metabolic panel to assess liver and kidney function
- Complete blood count
- Lipid panel
- Vitamin D levels
- Baseline bone density scan (DEXA)
- Pregnancy testing for those with uterine capacity A thorough physical exam including height, weight, blood pressure, and Tanner staging should also accompany laboratory evaluation to ensure safe administration of puberty blockers while monitoring for potential adverse effects.
From the Research
Laboratory Tests Prior to Initiating GnRH Agonists
To determine the recommended laboratory tests prior to initiating gonadotropin-releasing hormone (GnRH) agonists in adolescents, several studies provide relevant information.
- The following laboratory tests are recommended:
- These tests help assess the hypothalamic-pituitary-gonadal axis and determine the appropriate treatment approach for adolescents with disorders of puberty, including those who may benefit from GnRH agonists 2, 3, 4, 5.
Specific Considerations
- In patients with precocious puberty, additional tests such as brain magnetic resonance imaging may be necessary, especially in girls younger than six years, all boys with precocious puberty, and children with neurologic symptoms 5.
- For adolescents with delayed puberty, assessment of serum thyroid function, prolactin, and insulin-like growth factor I may be necessary if abnormal growth velocity is present 5.
GnRH Agonist Treatment Monitoring
- Laboratory tests, including serum LH and FSH levels, can be used to monitor the effectiveness of GnRH agonist treatment in suppressing the hypothalamic-pituitary-gonadal axis 2, 3, 4.
- Long-acting GnRH analogues, such as subcutaneous leuprolide acetate, have been shown to be effective in treating central precocious puberty and can be used for treatment monitoring 3.