What labs should I order to confirm menopause, specifically Follicle-Stimulating Hormone (FSH) and estradiol levels?

Laboratory Testing to Confirm Menopause

For women under age 60, measure both FSH and estradiol levels after 12 months of amenorrhea to confirm postmenopausal status, with FSH in the postmenopausal range and low estradiol supporting the diagnosis. 1, 2

Age-Based Diagnostic Approach

Women ≥60 Years

• No laboratory testing is required to diagnose menopause in women 60 years or older 1, 3
• Age alone is sufficient for clinical diagnosis in this population

Women <60 Years

For women under 60 with amenorrhea ≥12 months (in the absence of chemotherapy, tamoxifen, toremifene, or ovarian suppression):

• Measure FSH and estradiol levels 1, 2
• Postmenopausal ranges for both hormones confirm menopause
• The combination of elevated FSH and low estradiol provides stronger diagnostic certainty than either alone 2

Special Populations Requiring Testing

Women on tamoxifen or toremifene (age <60):

• FSH and plasma estradiol levels in postmenopausal ranges are required for diagnosis 1
• FSH alone is unreliable in this population 1

Women with chemotherapy-induced amenorrhea:

• FSH is not a reliable marker of menopausal status 1
• Serial estradiol measurements are more useful to determine return of ovarian function 1
• Consider serial measurements of FSH and/or estradiol if aromatase inhibitors are being considered 1

Women on GnRH agonists/antagonists:

• It is not possible to assign menopausal status while receiving these medications 1
• Oophorectomy or serial hormone measurements are needed if definitive status determination is required 1

Critical Limitations of FSH Testing

Why Single FSH Values Are Inadequate

FSH levels fluctuate dramatically during the menopausal transition:

• FSH can rise into the postmenopausal range and then fall back to premenopausal levels 4, 5
• Ovulatory cycles (and potential fertility) can occur after observing postmenopausal FSH levels 4, 5
• No single FSH cutoff value effectively distinguishes between menopausal stages 6
• The commonly recommended FSH cutoff of 40 IU/L is inappropriate by itself for clinical determination 6

Perimenopausal hormone patterns are highly variable:

• Postmenopausal FSH and LH levels can occur with high estrogen levels 5
• FSH and estradiol levels show minimal correlation with each other 7
• Hormone levels do not correlate reliably with age or years since menopause 7

Recommended Clinical Algorithm

1. Start with menstrual history and age 7

   • 12 months of amenorrhea is the primary diagnostic criterion
   • Age ≥60 years = menopause confirmed without testing 1, 3

2. For women <60 with amenorrhea ≥12 months:

   • Order FSH and estradiol together 1, 2
   • Use local laboratory definitions of postmenopausal ranges
   • Both should be in postmenopausal ranges to confirm diagnosis

3. For women on endocrine therapy or with chemotherapy history:

   • Consider serial measurements rather than single values 1
   • Monitor for clinical symptoms suggesting persistent ovarian function 1
   • Use high-sensitivity estradiol assays when available 1

Key Clinical Pitfalls to Avoid

• Do not rely on FSH alone - it has poor diagnostic accuracy during the transition 4, 6, 7
• Do not use hormone testing in women ≥60 - it adds no diagnostic value 1, 3
• Do not assume a single elevated FSH confirms menopause - ovulation can still occur afterward 4, 5
• Do not trust FSH in women on tamoxifen or after chemotherapy - it is unreliable in these contexts 1