Do you need AMH, insulin tests, or ultrasound to diagnose PMOS, previously called PCOS?
A clear-eyed look at what tests you actually need for PMOS diagnosis - and what the guideline says you can skip.
- Adult diagnosis uses 2 of 3 Rotterdam criteria - you may not need all three.
- AMH can substitute for ultrasound in adults, but not as a standalone diagnostic test.
- Adolescents: ultrasound and AMH are both not recommended for diagnosis.
- Routine fasting insulin is not recommended in standard PMOS care.
- HbA1c and fasting glucose matter more for ongoing management.
What tests do you actually need?
The short answer: Probably less than your search history suggests. Most adults can be diagnosed with PMOS using the Rotterdam criteria - needing two of three features: irregular ovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology (ultrasound) OR elevated AMH. If irregular cycles and hyperandrogenism are already present, ultrasound or AMH may not be necessary at all.1 And routine fasting insulin assays - despite how often they come up online - are not recommended in routine PMOS care.2
This isn't about denying you tests. It's about not paying for tests that don't change your treatment.
Adapted from the 2023 International Evidence-Based PMOS Guideline.
When AMH actually helps
The short answer: In adults, AMH can be used as an alternative to ultrasound for defining polycystic ovarian morphology. It's not a standalone PMOS test - it doesn't diagnose the condition by itself.1
AMH is useful when ultrasound isn't accessible, when ovarian morphology is unclear, or when you want to avoid transvaginal imaging. It's less useful as a screening test if you don't have other clinical features of PMOS. And in adolescents, both AMH and ultrasound are not recommended because specificity is poor during the years immediately following menarche.
What AMH does not do: predict severity, predict response to treatment, or replace a clinical conversation. It's one input among several.
When ultrasound is useful (and when it isn't)
The short answer: Ultrasound is useful when you don't already have the other diagnostic criteria established. If you have irregular cycles and clear hyperandrogenism, the guideline allows diagnosis without ultrasound at all.
If ultrasound is needed, the timing and approach matter. Transvaginal is more sensitive than transabdominal. The number of follicles required for "polycystic morphology" has been revised over time - current threshold uses higher counts than older studies - so an older ultrasound report calling your ovaries "polycystic" may or may not match current criteria.
If your only PMOS-related test was an ultrasound years ago, and you've never had hyperandrogenism evaluated clinically or biochemically, you may not have had a complete diagnostic workup.
Why fasting insulin is not the diagnostic hero
The short answer: The 2023 guideline is explicit: routine insulin assays have limited clinical relevance and are not recommended in routine PMOS care.2 Despite this, fasting insulin is one of the most commonly recommended labs in online PMOS communities.
Why the disconnect? Two reasons. First, insulin resistance is a real part of PMOS biology - that's why "metabolic" is now in the name. But a single fasting insulin test or a calculated HOMA-IR doesn't reliably predict who will respond to which treatment. Second, the tests themselves are technically inconsistent - different assays produce different numbers for the same patient.
The labs that do matter more for ongoing PMOS management: fasting glucose, HbA1c, lipid panel, and clinical signs of androgen excess. Those move treatment decisions. Fasting insulin alone rarely does.
Insulin assays should not be used in routine clinical care of PCOS, as the available tests have limited clinical relevance.
- 2023 International Evidence-Based PMOS Guideline2
The bottom line
What we know: Adult diagnosis uses 2 of 3 Rotterdam criteria. Ultrasound or AMH is needed when other features aren't already clear. Adolescent diagnosis is more conservative. Routine fasting insulin is not recommended.
What we don't know yet: Whether newer biomarkers will eventually outperform the current criteria. Whether different PMOS phenotypes warrant different testing approaches.
What to do next: If you've already met two criteria, you don't need a third test to confirm your diagnosis. Use your appointments to ask about metabolic and cardiometabolic screening over time, not more diagnostic tests.
References
- Teede HJ et al. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab. 2023. [Link]
- American Society for Reproductive Medicine. Recommendations from the 2023 International Evidence-based Guideline. [Link]
- Teede HJ et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome. The Lancet. 2026.
- Summary of the 2023 international evidence-based guideline for the assessment and management of PCOS. Medical Journal of Australia. 2024. [Link]