To diagnose polycystic ovary syndrome (PCOS) in young infertile women using different diagnostic criteria. To define serum anti-Mullerian hormone (AMH) cutoff values for PCOS definition. To investigate the correlation between AMH and body mass index (BMI).Retrospective case-control study. A total of 140 infertile women (age 21-35 years) were enrolled. PCOS was defined according to the National Institutes of Health (NIH) criteria, the Rotterdam consensus criteria and the Androgen Excess and PCOS Society (AE-PCOS) criteria. ROC curve analysis was performed to define AMH thresholds for PCOS definition according to the three different diagnostic criteria. Correlation between AMH and BMI was investigated.The prevalence of PCOS under the NIH criteria, the Rotterdam criteria and the AE-PCOS criteria was 27.1, 40 and 29.3%, respectively. The optimal thresholds of AMH to distinguish NIH PCOS from infertile controls was 5.20 ng/ml (AUC = 0.86, sensitivity 79%, specificity 80%); the best cutoff to detect Rotterdam PCOS was 4.57 ng/ml (AUC = 0.85, sensitivity 78%, specificity 81%); a cutoff of 4.85 ng/ml (AUC = 0.85, sensitivity 80%, specificity 78%) defined PCOS women according to AE-PCOS criteria. The prevalence of the syndrome became 37.1, 44.3 and 39.2% according to the three criteria, respectively, using AMH threshold between 4.57 and 5.20 ng/ml as an alternative to antral follicle count and/or hyperandrogenism.Anti-Mullerian hormone may reconcile the three diagnostic criteria and allow the PCOS diagnosis in women with mild symptoms. No significant correlation was found between AMH and BMI in PCOS women and controls
