--- title: "Hormone blood tests: what they can and cannot tell you" description: "What common hormone tests look for, why timing matters, and why an AMH result can’t forecast your future fertility. Includes when to get help." url: "https://myruva.co/learn/hormone-blood-tests-explained" language: "en-GB" topic: "Hormones" published: "2026-10-18" updated: "2026-10-19" author: "Ruva team" reading_minutes: 4 --- # Hormone blood tests: what they can and cannot tell you What common hormone tests look for, why timing matters, and why an AMH result can’t forecast your future fertility. Includes when to get help. *Written and reviewed by the Ruva team · Updated 2026-10-19 · Hormones* ## Key points - Hormone results need to be read alongside your symptoms, age and medical history. - Some blood tests need to be done at a certain point in your cycle. - AMH can’t tell you about egg quality or predict whether you’ll get pregnant. - From age 45, NICE usually uses symptoms rather than hormone tests to identify perimenopause. A hormone blood test can help answer a specific medical question. It can’t give you a full forecast of your fertility. Your clinician needs to look at the results alongside your symptoms, age, medical history and sometimes other tests. ## What the tests look for FSH stands for follicle-stimulating hormone. It helps eggs grow in the ovaries and gets them ready for ovulation. The test can help find out why periods have become irregular or stopped, and look into some fertility problems. When explaining the result, your clinician will think about why the test was asked for. LH (luteinising hormone) helps trigger the release of an egg. FSH and LH both come from the pituitary gland in the brain. An LH blood test may be part of a check. It’s different from a home ovulation test, which measures LH in urine. Oestradiol, a form of oestrogen, is often tested alongside FSH. If your periods have stopped, the results together can help a clinician see how the ovaries and hormone signals are working. A progesterone test taken at the right time can help show whether you’ve recently ovulated. TSH means thyroid-stimulating hormone. It can help find thyroid problems when checking why ovulation has been disrupted. Prolactin is a pituitary hormone. Its main jobs include helping the breasts develop during pregnancy and making milk afterwards. Raised prolactin can also affect the ovaries and periods. You may not need all of these tests. For example, ASRM doesn’t recommend a prolactin test as a routine part of every fertility check. It can be useful if you have milky fluid from the nipples, or periods that are rare or have stopped. Ask what each test is meant to find out. ## Timing can change what a result tells you Hormone levels change through the cycle. A clinician may ask for FSH and oestradiol early in the follicular phase (the first days of your cycle). Progesterone is usually checked later. ASRM recommends testing progesterone about 1 week before your next period is due, rather than assuming the same cycle day suits everyone. If your periods are hard to predict, ask the clinician who asked for the test when to have it. Give the first day of your last period if you know it, and say if you’re guessing. One progesterone result may help show that you ovulated. It can’t tell how well the second half of your cycle (the luteal phase) is working. Tell the clinician about any medicines and supplements before testing. Follow their instructions on how to prepare. Don’t stop a prescribed medicine without talking to your doctor. Ask who will explain the results and whether you might need another test. ## AMH is not a fertility expiry date Anti-Müllerian hormone (AMH) is made in the small sacs in the ovaries where eggs grow. It helps estimate ovarian reserve, which means the supply of eggs, and can help plan fertility treatment. It doesn’t measure egg quality or predict whether you’ll get pregnant. A home AMH test measures the same hormone, so paying for one privately doesn’t get around these limits. ASRM warns against using egg-supply tests as a random check on the ovaries in people who don’t have fertility problems. A result on its own can’t tell you it’s safe to wait before trying for a baby. It also can’t tell you that pregnancy is impossible. ## Why perimenopause often needs no blood test NICE advises identifying perimenopause without lab tests in otherwise healthy people aged 45 or over. This applies to people who have recently started having hot flushes or sweats and changes to their periods. MedlinePlus also says an FSH test usually isn’t needed at age 45 or older. Your symptoms and situation can give enough information. You don’t need a blood test to talk about care. Hormone treatments can make this harder to judge. NICE limits the use of FSH tests in people using combined hormonal contraception. It also sets separate limits on how its guidance applies to people taking gender-affirming hormones. Tell the clinician which treatments you use, rather than applying the usual age-based advice to yourself. ## When to arrange a review Book a GP appointment in the UK, or see your doctor in the US and elsewhere, if your periods become irregular or you miss your period 3 times in a row. Ask the clinician who ordered a test what question it answered, what is still uncertain and what happens next. Bring any results from private tests to that conversation too. ## When to get help - **Book an appointment:** Book a GP appointment (UK), or see your doctor (US and elsewhere), if your periods have recently become irregular, you miss your period 3 times in a row, or you have symptoms you want checked. Ask the clinician who ordered a test to explain the result and what happens next. ## Where you live Services and advice differ between countries. - **UK:** NICE advises identifying perimenopause without lab tests in otherwise healthy people aged 45 or over who have recently started having hot flushes or sweats and changes to their periods, within the scope of its guideline. - **US:** MedlinePlus says an FSH test usually isn’t needed at age 45 or older, though there may be medical reasons to test. - **Elsewhere:** Elsewhere, ask the clinician arranging the test how it works locally, when to have it and what follow-up to expect. ## Sources 1. [Follicle-Stimulating Hormone (FSH) Levels Test](https://medlineplus.gov/lab-tests/follicle-stimulating-hormone-fsh-levels-test/), MedlinePlus 2. [Anti-Müllerian Hormone Test](https://medlineplus.gov/lab-tests/anti-mullerian-hormone-test/), MedlinePlus 3. [Recommendations | Menopause: identification and management | Guidance | NICE](https://www.nice.org.uk/guidance/ng23/chapter/recommendations), NICE 4. [Missed or late periods](https://www.nhs.uk/symptoms/missed-or-late-periods/), NHS 5. [Luteinizing Hormone (LH) Levels Test](https://medlineplus.gov/lab-tests/luteinizing-hormone-lh-levels-test/), MedlinePlus 6. [Fertility evaluation of infertile women: a committee opinion (2021)](https://www.asrm.org/practice-guidance/practice-committee-documents/fertility-evaluation-of-infertile-women-a-committee-opinion-2021/), American Society for Reproductive Medicine 7. [Prolactin Levels](https://medlineplus.gov/lab-tests/prolactin-levels/), MedlinePlus 8. [Progesterone Test](https://medlineplus.gov/lab-tests/progesterone-test/), MedlinePlus --- This guide is general information to help you keep and use your own records. It isn’t medical advice. If you’re worried about a symptom, or something changes suddenly, talk to a doctor, nurse or pharmacist.