For years, getting a PCOS diagnosis often meant a transvaginal ultrasound. The 2023 international guideline changed that for adults, and a lot of people have not heard.
In adults, diagnosis needs two of these three, once other causes have been ruled out:
That third line is what changed. AMH — anti-Müllerian hormone — is a blood test, and the 2023 guideline accepts it as an alternative to ultrasound in adults. The evidence had been building since the previous edition, and the panel judged it strong enough.
If you have both irregular cycles and signs of excess androgens, you already meet two of the three criteria. In that case the guideline says ultrasound and AMH are not required at all.
Plenty of people have waited months for a scan they did not need. If that is your situation, it is a fair question to put to your doctor.
A transvaginal ultrasound is invasive, and for some people — those who have not been sexually active, anyone with a history of assault, or people who simply find it distressing — it is a real barrier to getting diagnosed at all. A blood draw is not the same thing.
It also removes a scheduling bottleneck. A blood test is easier to get than a scan in most healthcare systems, and delayed diagnosis is one of the most consistent complaints people with PCOS report.
Two important limits:
AMH is also used in fertility clinics as a rough marker of ovarian reserve. The same number is being read for a different purpose there, which is a common source of confusion.
Thyroid problems and raised prolactin can produce a similar picture, and both are simple blood tests. "Other causes excluded" is part of the criteria, not an optional extra.
Two of the three criteria depend on things you observe rather than things a lab measures. "My cycles are irregular" is much stronger with dates attached, and so is a record of when acne or unwanted hair changed.
PCOS Ai keeps that record and turns it into a summary you can hand over, so the appointment starts from your actual history. Our appointment guide covers what else is worth taking, and how long is too long between periods covers what counts as irregular.
General wellness information, not medical or dietetic advice. Nothing here diagnoses, treats or cures PCOS. Nutrition figures are per-serving estimates. Check with your doctor or a registered dietitian before making significant changes — especially if you are pregnant, breastfeeding, diabetic or managing a food allergy.