--- title: "How PCOS is diagnosed" description: "How symptoms, blood tests and scans fit together to diagnose PCOS, and why the checks are different for teenagers. No single test can diagnose PCOS." url: "https://myruva.co/learn/how-pcos-is-diagnosed" language: "en-GB" topic: "PCOS" published: "2026-10-18" updated: "2026-10-19" author: "Ruva team" reading_minutes: 4 --- # How PCOS is diagnosed How symptoms, blood tests and scans fit together to diagnose PCOS, and why the checks are different for teenagers. No single test can diagnose PCOS. *Written and reviewed by the Ruva team · Updated 2026-10-19 · PCOS* ## Key points - No single test can diagnose PCOS. - In adults, diagnosis brings together symptoms and test results, once other causes have been ruled out. - In adults, an AMH blood test can be used instead of a scan for part of the check, but it can’t diagnose PCOS on its own. - Scans and AMH are not recommended for diagnosing PCOS in teenagers. A scan report that mentions polycystic ovaries is only part of the picture. PCOS can’t be diagnosed from a scan alone, and some people with PCOS don’t need a scan at all. Diagnosis brings together your symptoms, medical history and a few chosen tests. PCOS now has a new name: polyendocrine metabolic ovarian syndrome (PMOS). Both names mean the same condition. This article uses PCOS because it’s the name you may already know. ## What clinicians look for in adults First, other causes are ruled out. Then the international guideline looks for two of these three features. One is signs of higher androgen activity (androgens are hormones such as testosterone). Another is problems with ovulation. The third is a certain look of the ovaries on an ultrasound scan. In adults, a blood test for anti-Müllerian hormone (AMH) can be used instead of a scan for that third feature. Androgen activity may be checked through your symptoms, an examination or blood tests. Ovulation is the release of an egg. Problems with it can show up as irregular or missing periods. A clinician needs to look at these features alongside your history and test results. If you’ve already been shown to have irregular cycles and higher androgen activity, you don’t need a scan or AMH for a diagnosis. If the ovaries do need checking, the guideline recommends either AMH or a scan, not both as a matter of routine. AMH on its own is not a test for PCOS. ## What the appointment may involve Your doctor may ask about your medical history, examine you and arrange blood tests. These can measure androgen hormones, look for other causes such as thyroid problems, and check your cholesterol or diabetes risk. In the UK, a GP may refer you to a gynaecologist or an endocrinologist. Other things that can disrupt ovulation include pregnancy, thyroid problems, raised prolactin and big changes in weight or exercise. Your clinician chooses tests based on your history. Checking for other causes is part of the process, even when PCOS seems likely. Tell the clinician if you use hormonal contraception. The combined pill changes hormone levels and makes androgen blood tests hard to read reliably. Ask the prescriber how this affects any tests. Don’t change prescribed contraception on your own to get ready for a test. Mention hair removal too. Unwanted hair growth deserves to be taken seriously even if the hair can’t be seen at the appointment. Say what you remove, where, and how it affects you. ## Why adolescent assessment is different In teenagers, a diagnosis needs two things, once other causes are ruled out. One is irregular periods that keep going for longer than expected for the time since the first period. The other is signs of higher androgen activity. Scan results and AMH are not recommended for diagnosing PCOS in teenagers. The guidance for teenagers says a scan of the ovaries and AMH are not recommended until 8 years after the first period. This limit applies to diagnosing PCOS. Symptoms can still be checked and treated. Someone with only part of the pattern may be described as “at risk”. They may be offered help with symptoms and follow-up. This leaves room to look at the diagnosis again as the pattern becomes clearer. Ask what will be reviewed and how to get help in the meantime. The NHS patient page gives a simpler message based on age: it says ultrasound is only done over 18. The international guidance for teenagers also looks at time since the first period. These two limits aren’t the same thing. So a birthday alone isn’t a reason to ask for an adult check based on a scan. ## Agreeing what happens next Book a GP appointment (UK), or see your doctor (US or elsewhere), if you think you may have PCOS or your symptoms affect everyday life. After diagnosis, the guideline recommends checking your blood sugar and cholesterol, and your blood pressure. These checks look at health risks linked to PCOS. They’re separate from the tests used to diagnose it. Before you leave, ask what supports the diagnosis and which other causes were looked at. Ask about anything that’s still uncertain. If the answer is “not clear yet”, ask for a follow-up plan and help with the symptoms that brought you in. You can ask for the explanation in plain language, and write down who to contact with more questions. ## When to get help - **Book an appointment:** Book a GP appointment (UK), or see your doctor (US or elsewhere), if you think you may have PCOS or your symptoms affect everyday life. ## Where you live Services and advice differ between countries. - **UK:** The NHS describes a check by a GP and a possible referral to a gynaecologist or a hormone specialist (endocrinologist). Its patient page says an ultrasound scan of the ovaries is only done over 18. - **US:** The Office on Women’s Health describes questions about your history, an examination and blood tests. ASRM publishes the international guideline, including the AMH option for adults. - **Elsewhere:** WHO says diagnosis comes after other causes are ruled out. The international guideline gives more detailed criteria for adults and teenagers. ## Sources 1. [Polycystic ovary syndrome](https://womenshealth.gov/a-z-topics/polycystic-ovary-syndrome), Office on Women's Health 2. [Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polyendocrine Metabolic Ovarian Syndrome](https://www.asrm.org/practice-guidance/practice-committee-documents/recommendations-from-the-2023-international-evidence-based-guideline-for-the-assessment-and-management-of-polyendocrine-metabolic-ovarian-syndrome-2023/), American Society for Reproductive Medicine 3. [Polyendocrine metabolic ovarian syndrome (PMOS)](https://www.nhs.uk/conditions/polyendocrine-metabolic-ovarian-syndrome-pmos/), NHS 4. [Polycystic ovary syndrome](https://www.who.int/news-room/fact-sheets/detail/polycystic-ovary-syndrome), World Health Organization 5. [Fertility evaluation of infertile women: a committee opinion](https://www.asrm.org/practice-guidance/practice-committee-documents/fertility-evaluation-of-infertile-women-a-committee-opinion-2021/), American Society for Reproductive Medicine 6. [International evidence-based recommendations for polycystic ovary syndrome in adolescents](https://pmc.ncbi.nlm.nih.gov/articles/PMC11899933/), BMC Medicine / PubMed Central --- 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.