The Rotterdam criteria are the PCOS diagnostic standard requiring two of three features after other causes are excluded.
What the Rotterdam criteria are
The Rotterdam criteria, introduced in 2003, are the most widely used framework for diagnosing PCOS. They are not a single test but a structured way to weigh several features together. A diagnosis is considered when two of three features are present. This approach helps a doctor assess the whole picture rather than relying on one finding alone. Because PCOS symptoms vary from person to person, a framework like this helps keep assessment more consistent between different doctors and over time. A basic overview of the condition is on the what is PCOS page.
The three features assessed
The three features are irregular or absent ovulation, often seen as irregular periods; signs of excess androgens, either clinical such as acne and excess hair, or on blood tests; and a polycystic ovarian appearance on ultrasound. Because there are several possible combinations, two people can both have PCOS yet present quite differently. This is why one person’s experience may not match another’s, and why care is often tailored to the individual. It is also why an ultrasound is not always needed when the other two features are already present. More about these symptoms is on the PCOS symptoms page.
Why other causes must be excluded
PCOS is a diagnosis of exclusion. Before the criteria are applied, a doctor needs to rule out other conditions such as thyroid problems, high prolactin, or congenital adrenal hyperplasia, because these can mimic similar symptoms. Without this exclusion step, another condition might be mistaken for PCOS, and this could delay the right treatment for the actual cause.
When to talk to a doctor
Only a doctor can judge whether these criteria are met in your situation, because it requires interpreting symptoms and test results together. Self-assessment from a list of features alone is not enough, because many other conditions can look similar. If you have symptoms such as irregular periods, talk to a doctor or pharmacist about the assessment that suits you. They can help decide which tests are needed and explain what each finding means.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.