Laboratory Testing for Menopause
Measure serum estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin as clinically indicated, but recognize that FSH is unreliable in women with prior chemotherapy, pelvic radiation, or those taking tamoxifen. 1, 2
When Laboratory Testing is Actually Needed
Laboratory confirmation is not routinely required for diagnosing menopause in most clinical scenarios. 1 The diagnosis is primarily clinical, based on:
- Age ≥60 years - no laboratory testing needed 1
- Age <60 years with 12+ months of amenorrhea in the absence of chemotherapy, tamoxifen, toremifene, or ovarian suppression - FSH and estradiol in postmenopausal range confirms diagnosis 1
- Prior bilateral oophorectomy - no laboratory testing needed 1
Specific Laboratory Tests and Their Interpretation
Primary Hormonal Assessment
FSH (Follicle-Stimulating Hormone):
- Elevated FSH (particularly in early follicular phase) indicates declining ovarian follicular activity 3
- Critical limitation: FSH is not reliable in women with prior chemotherapy, pelvic radiation exposure, or those on tamoxifen 1, 2
- During menopausal transition, hormone levels vary markedly, making FSH an unreliable guide to menopausal status 3
Estradiol:
- Postmenopausal range confirms ovarian failure 1
- Levels remain relatively unchanged or rise until late perimenopause, then fall profoundly over 3-4 years around final menses 3
- Serial estradiol levels are useful for perimenopausal/premenopausal women who became amenorrheic and later develop bleeding to determine return of ovarian function 1, 2
LH (Luteinizing Hormone):
Prolactin:
Additional Markers (Limited Utility)
Anti-Müllerian Hormone (AMH) and Inhibin:
- May provide additional information on ovarian status in women with prior chemotherapy or on tamoxifen 1
- Not reliable alone to ensure menopausal status 1
- Inhibin B reflects declining follicle numbers 3
When Taking Tamoxifen or Toremifene
If age <60 years and on tamoxifen/toremifene:
- Require both FSH and plasma estradiol in postmenopausal ranges to confirm menopausal status 1
- Single measurement insufficient due to fluctuating levels 1
Special Populations Requiring Testing
Women on LHRH agonists/antagonists:
- Cannot assign menopausal status while on these medications 1
- Requires oophorectomy or serial FSH/estradiol measurements if considering aromatase inhibitors 1
Premenopausal women post-chemotherapy:
- Amenorrhea is not reliable - ovarian function may resume despite anovulation 1
- Need oophorectomy or serial FSH/estradiol measurements to ensure postmenopausal status before aromatase inhibitor use 1
Suspected hypogonadism:
- Measure serum estradiol with LH/FSH if menstrual irregularity or evidence of hypogonadism in premenopausal women 1
- Low estradiol with inappropriately normal/low LH/FSH indicates hypogonadism 1
Complementary Laboratory Assessment
Rule out other causes of symptoms:
- Thyroid function tests - exclude thyroid disease mimicking menopausal symptoms 1
- Full blood count 1
- Liver and renal function tests 1
- Alkaline phosphatase and calcium - particularly if osteoporosis concern 1
- 25-OH vitamin D - if high risk for deficiency (housebound, malabsorption, chronic cholestasis) 1
Critical Clinical Pitfalls
Do not rely on single FSH measurement during perimenopause - hormone levels fluctuate markedly during the transition, making isolated measurements unreliable for determining menopausal status 3
Do not assume amenorrhea equals menopause in chemotherapy patients - ovarian function may be intact or resume despite anovulation, requiring serial hormonal measurements 1
Do not use FSH to guide aromatase inhibitor therapy without confirming postmenopausal status through serial measurements or oophorectomy in premenopausal women who received chemotherapy 1