Polycystic ovary syndrome (PCOS) is known one of the most common causes of menstrual irregularities and hyperandrogenism in adolescents. We compared cases with increased risk for PCOS (presence of clinical hyperandrogenemia (CH) and/or biochemical hyperandrogenemia (BH) along with menstrual irregularity (MI)) and cases with only MI. Patients were divided into four subgroups. Those with only MI (n=130), CH+MI (n=68), BH+MI (n=25), and CH+BH+MI (n=31). Age, weight, height, and body mass index were recorded. The CH was assessed by the presence of persistent acne, hirsutism, or androgenic alopecia. Modified Ferriman Gallwey (mFG) score was used to evaluate hirsutism. Cases with total testosterone levels above 55 ng/dL were considered to have BH. We observed that basal LH and LH/FSH ratio do not provide insight into CH. Unlike, DHEA-S (p=0.006), total testosterone (p=0.003), and free androgen index (FAI) (p=0.027) are relatively high in patients with CH. Polycystic ovarian morphology (PCOM) is lower in cases with only MI compared to cases with increased risk of PCOS (43.3 vs. 56.7 %, p=0.096). We predicted that 28.05 μg/L for Total testosterone, 75.9 for FAI, and 192.9 μg/dL for DHEA-S could be used as a cut-off value with a sensitivity and specificity over 60 %, ​​to distinguish MI from increased risk for PCOS. After excluding other secondary endocrinological causes of MI in the first years, routine use of total testosterone, DHEA-S, and FAI is sufficient to distinguish cases presenting menstrual disorders due to anovulation from increased risk of PCOS.