What labs should be checked to diagnose possible menopause?

Laboratory Tests for Diagnosing Menopause

The recommended laboratory tests for diagnosing menopause include follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and prolactin levels, as clinically indicated. 1

Primary Laboratory Evaluation

• FSH and LH: Elevated levels indicate declining ovarian function
  • FSH > 30 mIU/mL is typically consistent with menopause
  • Note: FSH alone is not a reliable marker in certain populations 1, 2
• Estradiol: Low levels (<20 pg/mL) support menopausal diagnosis
• Prolactin: To rule out hyperprolactinemia as a cause of symptoms

Important Considerations for Testing

Timing of Testing

• Collect samples in the early follicular phase (days 2-5) of menstrual cycle if cycles are still present
• For women with irregular cycles, testing can be done at any time
• Serial measurements may be necessary due to hormonal fluctuations during perimenopause 3, 4

Limitations of Testing

• FSH levels can fluctuate significantly during perimenopause, making a single measurement unreliable 2, 5
• FSH is not reliable in women with:
  • Prior chemotherapy exposure
  • Pelvic radiation history
  • Current tamoxifen use 1
  • Active hormone replacement therapy (HRT) 6

Additional Tests to Consider

1. Thyroid function tests: To exclude thyroid disease that may mimic menopausal symptoms 1
2. Anti-Müllerian hormone (AMH): May provide additional information on ovarian reserve, particularly in cancer survivors 1
3. Inhibin levels: Can provide supplementary information on ovarian status 1, 3

Special Situations

Women on Hormone Replacement Therapy

• Exogenous hormones suppress the hypothalamic-pituitary-gonadal axis, making FSH and LH unreliable 6
• For accurate assessment:
  • Temporarily discontinue HRT
  • Wait for clearance of exogenous hormones
  • Measure FSH and LH levels
  • Resume HRT after testing if indicated 6

Cancer Survivors

• More comprehensive evaluation may be needed
• Serial estradiol levels can help determine return of ovarian function 1
• Morning testosterone and free testosterone should be checked in male survivors if hypogonadism is suspected 1

Diagnostic Criteria for Menopause

• Age ≥60 years
• Age <60 years with amenorrhea for ≥12 months without chemotherapy, tamoxifen, or ovarian suppression AND FSH/estradiol in postmenopausal range
• Prior bilateral oophorectomy 6

When to Refer to Specialist

Consider referral to endocrinology/gynecology for:

• Persistently abnormal hormone levels
• Hypogonadism
• Diagnostic uncertainty 6

Remember that during the menopausal transition, hormone levels can vary markedly, making a single measurement of FSH and estradiol an unreliable guide to menopausal status 3. Multiple measurements over time provide more accurate assessment.