Getting diagnosed with PCOS typically involves a combination of a medical history review, blood tests for hormone levels, and sometimes a pelvic ultrasound. There is no single test that confirms it. Instead, your provider will look for at least two of three key features: irregular periods, signs of excess androgens (male-type hormones), and a specific ovarian appearance on ultrasound. The process also requires ruling out other conditions that can mimic PCOS, which is why diagnosis sometimes takes more than one appointment.
Which Doctor to See First
You can start with your primary care doctor, but you may be referred to a specialist. A gynecologist, an endocrinologist (hormone specialist), or a reproductive endocrinologist can all diagnose and manage PCOS. If your primary care provider is comfortable ordering the initial blood work and ultrasound, they can often make the diagnosis themselves and refer you only if needed.
The first visit will likely focus on your symptoms and medical history. Expect questions about your menstrual cycle length and regularity, any changes in weight, hair growth patterns, acne, and whether close family members have PCOS or diabetes. A physical exam typically checks for visible signs like excess hair growth, thinning hair on the scalp, acne along the jawline, and skin changes associated with insulin resistance, such as dark, velvety patches on the neck or underarms.
The Three Diagnostic Criteria
Most providers use the Rotterdam criteria, which require at least two of the following three features:
- Irregular or absent periods. This usually means cycles shorter than 21 days, longer than 35 days, or fewer than eight cycles per year. Some people with PCOS stop getting periods entirely.
- Excess androgens. This can show up clinically (visible signs like hirsutism, acne, or hair thinning) or biochemically (elevated hormone levels on blood work). You only need one or the other to meet this criterion.
- Polycystic ovarian morphology. This is a specific pattern on ultrasound showing many small follicles in the ovaries. Despite the name, these are not actually cysts. The current threshold is 20 or more follicles in at least one ovary, or an ovarian volume of 10 mL or greater.
You do not need all three. Someone with irregular periods and elevated testosterone but normal-looking ovaries on ultrasound still qualifies. Similarly, someone with regular periods could be diagnosed if they have both excess androgens and polycystic ovarian morphology.
Blood Tests Your Provider Will Order
Hormone blood work is typically drawn on day 2 or 3 of your menstrual cycle, when baseline hormone levels are most accurate. If your periods are very irregular or absent, your provider may draw blood at any time or use medication to induce a period first.
The core panel usually includes testosterone (total and free), a protein called sex hormone-binding globulin that affects how much testosterone is active in your body, and sometimes androstenedione or DHEAS, which are other androgens. Your provider may also check LH and FSH, two pituitary hormones whose ratio can support the diagnosis, though this alone is not definitive.
If your tests include fasting glucose, insulin, or cholesterol, you’ll need to fast for 8 to 12 hours beforehand. If only the hormone panel is being drawn, fasting is not required. Many providers check metabolic markers at the same visit because insulin resistance is so common in PCOS and affects treatment decisions.
Conditions That Must Be Ruled Out
A PCOS diagnosis is partly a diagnosis of exclusion, meaning your provider needs to confirm that your symptoms aren’t caused by something else. Several conditions produce overlapping symptoms. Thyroid disorders can cause irregular periods and weight changes. Elevated prolactin (a pituitary hormone) can stop periods and mimic PCOS. A form of congenital adrenal hyperplasia, present from birth but sometimes not detected until adulthood, raises androgen levels in a pattern that looks very similar to PCOS. More rarely, Cushing syndrome or androgen-producing tumors of the ovaries or adrenal glands need to be considered.
This is why your blood work may include a thyroid panel, a prolactin level, and a test called 17-hydroxyprogesterone to screen for adrenal hyperplasia. These are standard, not a sign that your provider suspects something more serious. If all of these come back normal and you meet two of the three Rotterdam criteria, the diagnosis is PCOS.
When Ultrasound Is Needed (and When It Isn’t)
Ultrasound is useful but not always necessary. If you clearly have both irregular periods and clinical or biochemical evidence of excess androgens, you already meet two of the three criteria, and an ultrasound won’t change the diagnosis. Many providers still order one to get a complete picture, and it can be helpful for checking ovarian health before fertility treatment.
A transvaginal ultrasound gives the most detailed view. If that’s not appropriate or preferred, a transabdominal ultrasound (over the belly) can be done instead, though it primarily reports ovarian volume rather than precise follicle counts because the image quality is lower. The threshold for polycystic ovarian morphology is 20 or more follicles per ovary on transvaginal imaging, or an ovarian volume of 10 mL or more on either type of scan.
AMH as an Alternative to Ultrasound
Anti-Müllerian hormone, or AMH, is a blood marker that reflects the number of small follicles in your ovaries. The 2023 international PCOS guidelines now recognize AMH as an alternative to ultrasound in adults when imaging is unavailable or impractical. AMH levels tend to be significantly higher in people with PCOS because of the large number of developing follicles.
That said, AMH is not yet a standalone diagnostic tool. It works best as a supporting piece of evidence, particularly in borderline cases where ultrasound findings are unclear. Standardization of AMH testing across different labs remains a challenge, so your provider will interpret the result in context rather than relying on a single cutoff number.
Diagnosis in Teens
PCOS can be diagnosed during adolescence, but the criteria are stricter. Irregular periods are common in the first few years after a first period, so what counts as “irregular” depends on how long ago periods started. In the first year after menarche, cycles longer than 90 days raise concern. By the third year, cycles shorter than 21 days or longer than 35 days are considered irregular for diagnostic purposes.
The biggest difference for teens: ultrasound findings and AMH levels should not be used to diagnose PCOS until at least eight years after the first period. Before that point, it’s normal for ovaries to have a polycystic appearance, and AMH is naturally higher in younger people. The diagnosis in adolescents rests on just two pillars: clearly irregular cycles and evidence of excess androgens, after other conditions have been excluded.
If a teen has symptoms that are suggestive but not definitive, providers may label the situation “at risk for PCOS” and monitor over time rather than assigning a firm diagnosis too early.
How Excess Hair Growth Is Assessed
Clinical hyperandrogenism, the visible kind, is most commonly evaluated through a scoring system for excess hair growth called the Ferriman-Gallwey scale. Your provider scores hair density across nine body areas, including the upper lip, chin, chest, abdomen, and thighs. Each area gets a score from 0 to 4, and the numbers are added up.
A total score of 8 or higher is widely accepted as the threshold for hirsutism in most Western populations, corresponding roughly to the 95th percentile. However, this varies by ethnicity. Studies of Chinese women found the 95th percentile at a score of 7. Some recent guidelines have suggested using lower cutoffs of 4 to 6, but this remains debated among specialists. If your score falls in a gray zone, biochemical androgen testing becomes especially important for confirming the diagnosis.
Acne and scalp hair thinning are also recognized as signs of excess androgens, though they’re less standardized in scoring. Persistent, treatment-resistant acne along the jawline and lower face in an adult is a common presentation that prompts providers to investigate PCOS.
What Happens After the Diagnosis
Once PCOS is confirmed, your provider will typically screen for related metabolic issues if they haven’t already. This includes fasting glucose or an oral glucose tolerance test to check for insulin resistance or prediabetes, a lipid panel, and sometimes blood pressure monitoring. These screens matter because PCOS increases long-term risk for type 2 diabetes and cardiovascular problems, regardless of body weight.
Treatment depends on what’s bothering you most. If irregular periods are the main concern, hormonal options can regulate your cycle and protect the uterine lining. If excess hair growth or acne is the priority, different approaches target androgen effects. If you’re trying to conceive, the plan shifts toward ovulation support. Many people with PCOS also benefit from lifestyle changes that improve insulin sensitivity, which can in turn help with cycle regularity and other symptoms. Your provider will tailor the plan to your specific goals rather than applying a one-size-fits-all protocol.