Use of FSH levels

1. NICE recommendations

NICE says consider using a serum FSH test to confirm menopause only in:

• People aged 40–45 years with menopause symptoms, including a change in their menstrual cycle.
• In people <40 years in whom menopause is suspected.

2. How to perform FSH testing

• Serial measures should be undertaken, and most guidelines recommend checking two FSH blood samples taken 4–6 weeks apart.
• If there are still periods, a blood test for FSH should be taken on day 2-3 of the cycle.
• FSH levels should not be checked in a woman already using HRT, combined contraception or high dose progestogen.

3. Interpreting FSH results

• Levels of FSH >30IU/L are generally considered to be elevated and is the cut-off used by both NICE and the British Menopause Society. The ESHRE guideline suggests a slightly lower cut-off of >25IU/L.
• Levels of FSH fluctuate markedly on virtually a daily basis during the perimenopause and as a result, their diagnostic use is severely limited during this time. After menopause, FSH levels become persistently raised.
• The FSRH states that a single elevated serum FSH level (>30IU/L) indicates a degree of ovarian insufficiency, but not necessarily sterility.