When should a hormone test be considered?

When to Perform Hormone Testing

Hormone testing should be performed when there are clinical signs and symptoms suggestive of hormone dysfunction, in high-risk individuals, or for monitoring patients on certain therapies, rather than as a routine screening test for the general population. 1

Indications for Hormone Testing

Clinical Symptoms and Signs

• Thyroid Dysfunction:

  • Hypothyroidism: Fatigue, weight gain, cold intolerance, dry skin, constipation, menstrual irregularities 1
  • Hyperthyroidism: Weight loss, palpitations, heat intolerance, tremor 1

• Adrenal Dysfunction:

  • Cushing's syndrome: Central obesity, moon facies, buffalo hump, purple striae, hypertension, hyperglycemia 1
  • Adrenal insufficiency: Fatigue, weight loss, hypotension, hyperpigmentation 1

• Gonadal Dysfunction:

  • Males: Decreased libido, erectile dysfunction, decreased energy, reduced muscle mass, decreased body hair 2
  • Females: Menstrual irregularities, infertility, hirsutism, acne 1

High-Risk Populations

Hormone testing should be considered in:

1. Patients with previous radiation treatment of the thyroid gland 1
2. Patients with previous thyroid surgery or thyroid dysfunction 1
3. Patients with type 1 diabetes mellitus 1
4. Patients with personal history of autoimmune disease 1
5. Patients with family history of thyroid disease 1
6. Patients with atrial fibrillation 1
7. Women older than 60 years 1
8. Women planning pregnancy with risk factors for thyroid disease 1
9. Patients on immune checkpoint inhibitors requiring monitoring for immune-related endocrinopathies 1
10. Patients with adrenal incidentalomas 1

Monitoring Specific Conditions

• Patients on immune checkpoint inhibitors:

  • Monitor morning ACTH and cortisol levels every month for 6 months, then every 3 months for 6 months, then every 6 months for 1 year 1

• Patients with adrenal incidentalomas:

  • Perform 1mg dexamethasone suppression test to evaluate for autonomous cortisol secretion 1
  • Test for aldosterone/renin ratio in hypertensive patients or those with hypokalemia 1
  • Test for plasma free metanephrines if lesion has >10 HU on non-contrast CT 1

• Athletes with bone stress injury or menstrual dysfunction:

  • Screen for hormonal imbalances related to low energy availability 1

Specific Hormone Tests to Consider

Thyroid Function

• TSH and free T4 (first-line) 1
• Thyroid antibodies (TPO) if hypothyroidism is confirmed 1

Adrenal Function

• Morning cortisol and ACTH 1
• 1mg overnight dexamethasone suppression test 1
• Aldosterone/renin ratio (for suspected hyperaldosteronism) 1
• Plasma free metanephrines (for suspected pheochromocytoma) 1

Gonadal Function

• Males: Morning total testosterone (8-10 AM), LH, FSH 2
• Females: Estradiol, FSH, LH, progesterone (timing depends on menstrual cycle) 1

When NOT to Test

• General population screening for thyroid dysfunction is not recommended by the U.S. Preventive Services Task Force 1
• Routine hormone testing in asymptomatic patients under age 60 without risk factors 1
• Hormone testing in women taking hormonal contraception (results may be unreliable) 1

Important Considerations

• Timing of testing is crucial for accurate interpretation:

  • Testosterone should be measured in the morning (8-10 AM) 2
  • Cortisol should be measured in the morning (around 8 AM) 1
  • Female hormone tests should consider menstrual cycle phase 1

• Confirmatory testing is often necessary:

  • Repeat abnormal testosterone measurements on a different day 2
  • Consider specialized testing (e.g., TRH stimulation test) when clinical suspicion is high despite normal baseline tests 3

• Interpretation should consider factors that affect hormone levels:

  • Obesity can lower testosterone and SHBG levels 2
  • Liver disease can elevate SHBG levels 2
  • Insulin resistance is associated with low SHBG levels 2

By following these guidelines for hormone testing, clinicians can appropriately identify and manage hormone-related disorders while avoiding unnecessary testing in low-risk, asymptomatic individuals.