Your Complete Guide to Diagnosis
Navigating the path to a PCOS diagnosis can feel overwhelming. You may have already experienced months or even years of irregular cycles, frustrating symptoms, and perhaps even dismissive comments from healthcare providers. The reality is that PCOS cannot be diagnosed with a single test. Rather, it requires careful testing that rules out other conditions while confirming the key features of PCOS itself.
If you're waiting for answers or simply want to understand what your test results mean, this guide will walk you through the entire diagnostic journey. Knowledge is power, and understanding the "why" behind each test can help you advocate for yourself and feel more confident in your diagnosis.
Why PCOS Diagnosis Isn't Straightforward
PCOS is what doctors call a "diagnosis of exclusion." This simply means that before confirming PCOS, your healthcare provider must first rule out other hormonal conditions that look similar. Thyroid problems, elevated prolactin (a hormone that affects menstruation), and a condition called nonclassic congenital adrenal hyperplasia can all cause irregular periods and excess male hormones (a.k.a androgens), just like PCOS.
Once these conditions are excluded, your provider will look for the three core features of PCOS: high male hormones (androgens), irregular or missing ovulation, and polycystic-appearing ovaries. According to the internationally recognised Rotterdam criteria, you need at least two of these three features for a confirmed diagnosis.
The Three Core Features of PCOS
Your healthcare provider will assess three key areas to determine whether you have PCOS. Let's explore each one and the tests used to evaluate them.
Feature 1: Excess Male Hormones (Hyperandrogenism)
Excess male hormones are perhaps the most characteristic feature of PCOS. Your doctor can detect this either by examining you physically or through blood tests.
Physical Signs: Unwanted, Excess Hair Growth (Hirsutism)
Hirsutism means excessive hair growth in typically male-pattern areas such as your face, chest, abdomen, and back. Your healthcare provider may use a scoring system called the Modified Ferriman-Gallwey scale, which assigns points based on hair growth in nine body areas. A score of 4-6 or higher (depending on your ethnic background) indicates hirsutism.
The presence of hirsutism alone is considered a strong indicator of PCOS in adult women and may be enough to confirm excess male hormones. However, not all women with PCOS experience unwanted hair growth.
Blood Tests: Measuring Testosterone Levels
Your doctor may order several testosterone tests:
- Total Testosterone: Measures all the testosterone in your blood, both the active and inactive forms.
- Free Testosterone: Measures only the active testosterone that's available for your body to use.
- Free Androgen Index (FAI): A calculation that estimates your free testosterone using your total testosterone and a protein called SHBG (sex hormone-binding globulin) that carries testosterone in your blood.
These tests are ideally done in the morning when testosterone levels are highest. If you have somewhat regular cycles, testing during the first half of your cycle gives the most accurate results. Elevated levels indicate excess male hormones, supporting a PCOS diagnosis.
Additional Hormone Tests
Sometimes doctors test for other male hormones like androstenedione and DHEAS (both produced by your adrenal glands and ovaries). These tests might be ordered if your testosterone levels appear normal but your doctor still suspects PCOS based on your symptoms. However, these tests are less commonly used.
Important note about birth control: If you're taking the contraceptive pill, it lowers your natural hormone levels, making it difficult to get accurate testosterone readings from blood tests. Your provider may recommend stopping the pill for at least three months before testing if these results are crucial for your diagnosis.
Feature 2: Irregular or Absent Ovulation
Ovulation is when your ovary releases an egg each month. With PCOS, this process often doesn't happen regularly or at all.
How It's Assessed
Most of the time, your doctor can determine if you're ovulating based on your menstrual history. Signs of irregular ovulation include:
- Cycles longer than 35 days
- Fewer than 8 periods per year
- Complete absence of periods (amenorrhoea)
These patterns strongly suggest you're not ovulating regularly, which is one of the three core features needed for a PCOS diagnosis.
Progesterone Test
If your cycles seem fairly regular but PCOS is still suspected, your provider may order a progesterone blood test. Progesterone is a hormone that rises after ovulation, so this test is typically done about 7 days after you're expected to ovulate (day 21 of a 28-day cycle). Low progesterone indicates you didn't ovulate that cycle.
Why This Matters
Ovulation problems don't just affect your period. They can impact your ability to get pregnant, influence your metabolism, and increase your long-term health risks including heart disease and diabetes.
Feature 3: Polycystic-Appearing Ovaries
Despite the name, "polycystic ovaries" don't actually contain cysts. Instead, they have multiple small fluid-filled sacs called follicles, which are the structures that hold your developing eggs.
Important note: Many women with PCOS can be diagnosed based on excess male hormones and irregular cycles alone, without ever needing their ovaries assessed. Your doctor will typically only order these tests if the first two criteria aren't enough to make a diagnosis.
Pelvic Ultrasound
This is similar to the scan used during pregnancy, but it focuses on your ovaries to check their size and count the number of follicles present.
The most accurate method is a transvaginal ultrasound, where a small probe is gently inserted into your vagina to get a close-up view. If you're uncomfortable with this or it's not appropriate for you, an abdominal ultrasound (over your lower belly) can be used instead, though it's less detailed.
Your ovaries are considered "polycystic" if:
- You have 20 or more small follicles (2–9 mm in diameter) in at least one ovary, OR
- At least one ovary has a volume of 10 mL or more
Meeting these criteria supports a PCOS diagnosis, but here's something important to know: up to 20-30% of women without PCOS also have polycystic-appearing ovaries on ultrasound. This is why polycystic ovaries alone aren't enough for diagnosis.
Anti-Müllerian Hormone (AMH) Test
AMH is a hormone produced by the developing follicles in your ovaries. Women with PCOS typically have higher AMH levels because they have more follicles than average.
This is a simple blood test that can be done at any point in your cycle. Elevated AMH can be used as an alternative to ultrasound for assessing your ovaries, according to current international guidelines. This can be particularly helpful if you can't or prefer not to have a pelvic ultrasound.
Important limitation: AMH should never be used alone to diagnose PCOS. It must be considered alongside your other symptoms and test results. Additionally, AMH levels vary with age, ethnicity, and even between different laboratories. AMH testing is also not recommended for adolescents as levels are normally high during puberty, therefore the results will be less helpful.
Ruling Out Other Conditions
Before confirming PCOS, your doctor needs to ensure your symptoms aren't caused by something else. Several other hormonal conditions can look remarkably similar to PCOS, so these tests are essential.
Thyroid Function Test (TSH)
Your thyroid is a butterfly-shaped gland in your neck that controls your metabolism. TSH (thyroid-stimulating hormone) is produced by your pituitary gland in your brain and tells your thyroid how much thyroid hormone to produce.
Both an underactive thyroid (hypothyroidism) and overactive thyroid (hyperthyroidism) can cause irregular periods, weight changes, and fatigue, symptoms that overlap significantly with PCOS.
This is a simple blood test, usually done in the morning. Abnormal TSH levels indicate a thyroid problem rather than PCOS. Normal TSH levels help confirm that your thyroid isn't the culprit behind your symptoms.
It's worth noting that thyroid problems can occur alongside PCOS, but this screening helps determine if thyroid dysfunction is contributing to what you're experiencing.
Prolactin Test
Prolactin is a hormone made by your pituitary gland. While it's best known for its role in breast milk production, elevated prolactin levels (called hyperprolactinemia) can disrupt your menstrual cycle and prevent ovulation.
This blood test is ideally done in the morning when prolactin levels are most stable. You should be fasting and relaxed, as stress and even eating can temporarily raise prolactin levels.
Elevated prolactin might indicate a benign (non-cancerous) tumour on your pituitary gland called a prolactinoma, certain medications, or other conditions. Normal prolactin levels help support a PCOS diagnosis by ruling out this alternative explanation for your symptoms.
17-Hydroxyprogesterone (17-OHP) Test
This hormone is part of the pathway your body uses to produce cortisol (your stress hormone). Significantly elevated levels suggest a genetic condition called nonclassic congenital adrenal hyperplasia (NCAH), which affects your adrenal glands (small glands that sit on top of your kidneys).
Your doctor will order this test if they suspect NCAH based on your symptoms. It's done early in the morning (between 8 and 10 AM) during the first 5 days of your period if possible, as levels fluctuate throughout the day and your cycle.
NCAH can cause excess male hormones and irregular cycles, making it look very similar to PCOS, but it requires different treatment. Normal levels help rule out this condition.
When Additional Testing Is Needed
If your symptoms are particularly severe or getting worse rapidly, such as sudden deepening of your voice, significant enlargement of the clitoris, or dramatic new hair growth, your provider may order additional tests. These help rule out rare but serious conditions like androgen-secreting tumours (growths that produce male hormones) or Cushing's syndrome (a condition caused by too much cortisol). These tests would include checking for very high testosterone and DHEAS levels, along with specialised scans.
Special Considerations for Younger Women
Diagnosing PCOS in teenagers and young women under 20 is particularly tricky. Why? Because irregular periods and multiple follicles in the ovaries are completely normal during the first few years after your first period. Your reproductive system needs time to mature and establish regular cycles.
How PCOS is diagnosed in adolescents:
- Diagnosis requires persistent irregular periods (lasting at least two years after your first period) combined with physical signs of high male hormones (like significant hirsutism or severe acne) and/or blood tests confirming elevated androgens.
- Pelvic ultrasound and AMH testing are generally not recommended for teenagers.
- Doctors take a more cautious, conservative approach to avoid misdiagnosis.
Why this matters: Giving a young woman a PCOS diagnosis too early can cause unnecessary anxiety and stress. However, when the diagnosis is appropriate, early intervention can prevent long-term health complications.
Your Diagnostic Journey: What to Expect
The path to a PCOS diagnosis typically unfolds like this:
Initial consultation: You'll discuss your symptoms, menstrual history, and health concerns with your healthcare provider. Be honest and thorough, every detail matters.
Comprehensive blood work: Your doctor will order blood tests to rule out thyroid problems, elevated prolactin, and NCAH (through TSH, prolactin, and 17-OHP tests), as well as to check for excess male hormones (testosterone tests). They'll also evaluate your menstrual patterns to assess whether you're ovulating regularly.
Additional assessment if needed: If the results aren't conclusive, your provider may order a pelvic ultrasound or AMH test to examine your ovaries.
Diagnosis confirmation: If you meet at least two of the three core criteria (excess male hormones, irregular ovulation, polycystic-appearing ovaries), you'll receive a PCOS diagnosis.
Follow-up screening: Your doctor will likely recommend additional tests to assess your metabolic health, including glucose tolerance testing (to check how your body processes sugar), insulin levels, cholesterol panels, and blood pressure monitoring. Why? Because PCOS increases your risk for insulin resistance, type 2 diabetes, and heart disease.
What to Do With Your Diagnosis
Receiving a PCOS diagnosis can trigger mixed emotions. You may feel relieved to finally have an explanation for your symptoms, yet overwhelmed by what it means for your health and future. Here's what you need to know: PCOS is manageable, and early diagnosis opens the door to interventions that can dramatically improve your quality of life.
Your next steps:
Lifestyle modifications: Research consistently shows that weight management can significantly improve hormone balance, insulin sensitivity, and ovulation in women with PCOS. Focus on a Mediterranean-style eating pattern rich in whole foods, engage in regular physical activity you enjoy, manage stress through techniques like mindfulness or yoga, and prioritise quality sleep. These aren't just suggestions, they're the foundation of effective PCOS management.
Nutritional support: Research-backed supplements like our Inositol Complex can help address insulin resistance (when your body doesn't respond well to insulin), reduce male hormone levels, improve egg quality, and support regular ovulation. Multiple studies have shown that inositol enhances both metabolic and reproductive outcomes in women with PCOS.
Medical management: Depending on your symptoms and goals, whether you're trying to conceive, manage unwanted hair growth, or regulate your cycles, your healthcare provider may recommend medications for additional support.
Mental health support: Don't underestimate the emotional toll of PCOS. The anxiety, depression, and stress associated with this condition are real and valid. Working with a mental health professional who understands PCOS can help you navigate the challenges with greater resilience and self-compassion.
You're Not Alone
PCOS affects 1 in 10 women of reproductive age. You are part of a global community of women who understand your struggles and are here to support you.
If you're still waiting for a diagnosis, don't hesitate to advocate for yourself. Ask questions, request the appropriate tests, and seek a second opinion if you feel your concerns are being dismissed. Your health matters, your symptoms are real, and you deserve comprehensive, compassionate care.
By understanding the diagnostic process, you're already taking an empowered step toward reclaiming your health. Whatever your PCOS journey looks like, know that with the right support, evidence-based interventions, and self-compassion, you can thrive.
Disclaimer: This article is for educational purposes only and should not replace personalised medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment recommendations specific to your individual situation.