What tests should be ordered for checking hormone levels?

Recommended Hormone Tests for Comprehensive Evaluation

For a comprehensive hormone evaluation, order thyroid function tests (TSH, free T4), sex hormones (testosterone, estradiol, FSH, LH), and cortisol levels, with additional specialized tests based on clinical presentation and suspected endocrine disorders. 1

Thyroid Function Testing

• Basic thyroid panel: TSH and free T4 should be ordered for all patients with suspected thyroid dysfunction 1
• Free T4 measurement is preferred over total T4 as it represents the biologically active hormone fraction and is not affected by binding protein variations 2
• Include thyroid antibody testing (TPO antibodies) when autoimmune thyroid disease is suspected 1
• Morning testing is preferred for consistency in serial measurements 1

Sex Hormone Testing

For Women:

• Basic panel: Estradiol, FSH, LH (drawn between days 3-6 of menstrual cycle for cycling women) 1
• For suspected PCOS: Add testosterone, androstenedione, and DHEAS 1
• Calculate free testosterone when total testosterone is borderline or when SHBG abnormalities are suspected 1, 3
• Consider prolactin measurement when galactorrhea, amenorrhea, or pituitary dysfunction is suspected 1
• Progesterone (measured mid-luteal phase) to assess ovulation 1

For Men:

• Basic panel: Total testosterone, free testosterone, SHBG, FSH, LH 1
• Morning testosterone measurements (between 8-10 AM) are essential due to diurnal variation 1
• Free testosterone by equilibrium dialysis is the gold standard when available 1
• Consider estradiol testing in men with gynecomastia 1

Adrenal Function Testing

• Basic adrenal assessment: Morning cortisol (8 AM) 1
• For suspected adrenal insufficiency: ACTH stimulation test 1
• For suspected Cushing's syndrome: 1 mg overnight dexamethasone suppression test 1
• Consider DHEAS when adrenal androgen excess is suspected 1

Metabolic and Additional Testing

• Glucose metabolism: Fasting glucose, insulin (calculate glucose/insulin ratio for insulin resistance) 1
• Consider HbA1c when diabetes is suspected 1
• Electrolytes including calcium, phosphate, and magnesium when evaluating parathyroid function or in patients on certain medications 1

Special Considerations

• Timing matters: Hormones with circadian rhythms (cortisol, testosterone) should be measured in the morning 1
• Menstrual cycle phase: For women, document cycle day when measuring reproductive hormones 1, 4
• Medication interference: Note medications that may affect hormone levels (e.g., oral contraceptives, glucocorticoids, anticonvulsants) 1
• Binding proteins: Consider measuring binding proteins (SHBG, TBG) when total hormone levels don't match clinical picture 2, 5

Imaging Considerations

• Pelvic ultrasound for women with suspected PCOS (days 3-9 of cycle) 1
• Consider pituitary MRI when central endocrine disorders are suspected 1

Common Pitfalls to Avoid

• Relying solely on total hormone levels when free hormone levels may be more clinically relevant 2, 5
• Failure to consider binding protein abnormalities that affect interpretation of total hormone levels 2
• Not accounting for diurnal variation or menstrual cycle timing when ordering tests 1
• Interpreting isolated hormone values without clinical context or related hormone measurements 1
• Using inappropriate reference ranges (not age or sex-specific) 1

Remember that hormone testing should be guided by clinical suspicion and symptoms rather than as a general screening tool in asymptomatic individuals 1.