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Blood test

FSH test

FSH test: what it measures, why a doctor orders it, how to prepare, and what a high or low result can mean - with private and NHS access routes in the UK.

Key facts

At a glance

  • What it measures: follicle-stimulating hormone, the pituitary hormone that ripens eggs in women and supports sperm production in men.

  • Why it is ordered: in fertility work-ups, premature ovarian insufficiency, selected menopause assessments, and male infertility.

  • No fasting is needed; in menstruating women a day 2-5 sample is standard.

  • Reference ranges: FSH rises as the ovary’s egg supply falls, which is why it climbs towards and after menopause. Every laboratory publishes its own interval, so the range printed on your report is the one that applies to you.

  • A raised result in a younger woman on repeated testing raises the question of premature ovarian insufficiency; in men it suggests the testes themselves are underperforming. A low result with low LH suggests a pituitary cause for absent periods or low hormones.

  • Results are usually back within 24-48 hours when taken privately, and often the same day for urgent requests.

The full picture

What this test tells you, and how to get it

The FSH test measures follicle-stimulating hormone, the pituitary hormone that ripens eggs in women and supports sperm production in men. Doctors most often request it in fertility work-ups, premature ovarian insufficiency, selected menopause assessments, and male infertility. No fasting is needed; in menstruating women a day 2-5 sample is standard. FSH rises as the ovary’s egg supply falls, which is why it climbs towards and after menopause, and reference intervals genuinely differ between laboratories, so no single number should be treated as a universal cut-off - your result is always read against the range printed on your own report. Broadly, a raised result in a younger woman on repeated testing raises the question of premature ovarian insufficiency; in men it suggests the testes themselves are underperforming, while a low result with low LH suggests a pituitary cause for absent periods or low hormones, and either finding is interpreted alongside your symptoms, medication and other results rather than in isolation. Results are usually back within 24-48 hours when taken privately, and often the same day for urgent requests.

In the UK there are two routes to this test. Your NHS GP can arrange it free of charge when it is clinically indicated, though getting the appointment, the blood draw and the follow-up discussion can add days to weeks depending on local demand. Privately, the FSH test can usually be booked within days - through a private GP, a walk-in phlebotomy clinic or a self-request home-testing service - as the standard partner to LH. A private result still deserves a clinician's interpretation: an isolated number without context is where most confusion about blood tests begins.

A quiet reminder

This guide is for information, not medical advice.

Your own clinician knows your history and can tell you which parts apply to you. Reference ranges vary between laboratories - always read your result against the interval printed on your own report. Next review of this page: 2027-09-27.

Frequently asked

Common questions about FSH test.

Quick, plain-English answers to what people ask us most.

  • What is an FSH test?

    Follicle-stimulating hormone, or FSH, is a hormone produced by the pituitary gland that plays a key role in regulating the menstrual cycle and sperm production. An FSH blood test measures its level to help assess fertility and reproductive hormone health.

  • Why would a doctor order an FSH test?

    It's commonly used to investigate fertility concerns, irregular periods, or suspected menopause or perimenopause in women, and to assess sperm production issues in men. It's often measured alongside LH, oestradiol, and other hormones for a fuller picture.

  • Do I need to prepare for it?

    For women, FSH is often best measured on a specific day of the menstrual cycle, usually day two or three, so timing matters and your doctor will advise on this. No fasting is generally required.

  • What happens during the test?

    It's a simple blood test taken from a vein in your arm, often done alongside other hormone tests in the same blood draw.

  • Does it hurt or have risks?

    Only the usual minor discomfort of a blood draw, with no significant risks involved.

  • How long do results take?

    Results are typically available within a few days.

  • What do abnormal results mean, and what happens next?

    A raised FSH in women can suggest reduced ovarian reserve or menopause, while low levels can indicate issues with the pituitary gland; in men, raised FSH can point to problems with sperm production. Your doctor will interpret the result alongside your symptoms, cycle timing, and other tests before discussing next steps.

  • How much does it cost privately, and is it available on the NHS?

    FSH testing is available on the NHS through GP or fertility clinic referral, though non-urgent appointments can take time to arrange. Private hormone testing is typically available within days, with specialist review, and cost varying by provider.

  • Is it accurate and reliable?

    FSH testing is a well-established, reliable hormone test, though results can vary naturally through the cycle and with age, so timing and context matter for accurate interpretation. It's most informative when considered alongside other fertility hormone tests rather than alone.

  • How do I book it privately, and how quickly can I be seen?

    You can book a private hormone blood test, timed appropriately to your cycle if relevant, with results usually available within a few days.