Evaluation of an adolescent for polycystic ovary syndrome requires both clinical and laboratory evaluations and consideration of ultrasound investigation as well (Table 6.2). A detailed menstrual history should be obtained to confirm oligomenorrhea and/or polymenorrhea and that the patient is 2 years postmenarche. Oligomenorrhe a is defined as menses occurring less than every 3 months with cycles >35 days in adults and >45 days in adolescents. Polymenorrhea is defined as menses with <25 day intervals for adults and <20 day interval cycles in adolescents [1, 2]. Primary amenorrhea in a small subset of girls may delay diagnosis of PCOS, but lack of menarche by age 15 or 2–3 years after true thelarche raises suspicion for PCOS.

Transabdominal or transvaginal ultrasound can be obtained to screen for polycystic ovarian morphology with transvaginal imaging preferred but not possible or tolerated in many adolescent patients. To meet criteria for PCOS, an adult ultrasound would demonstrate ≥12 antral follicles in at least one ovary measuring 2–9 mm in diameter or ovarian volume ≥ 10 cm³. However, in an adolescent, an ovarian volume ≥ 12 cm³ has been recommended by some authorities, and multifollicular morphology should not be used as this morphology may be difficult to distinguish from adolescent patterns. String of pearl morphology is sometimes but not necessarily found in adolescent evaluation of the ovaries by ultrasonography.

Hyperandrogenism in PCOS can be defined as either biochemical, with mild elevation of free and/or total testosterone , with free testosterone elevation more common, or clinical, based on physical exam features of androgen excess, mainly hirsutism, severe acne, or alopecia. Alopecia is uncommon in adolescence. The Ferriman-Gallwey score can be used for documenting hirsutism with a score of 8 or more consistent with hirsutism in Caucasian or African American girls . However, there can be ethnic variation in hirsutism affecting sensitivity of the scores, and some adolescents will have focal hirsutism but not elicit a high Ferriman-Gallwey score. Hirsutism refers specifically to excessive coarse sexual hair (terminal hair developing in a male pattern distribution) and must be distinguished from hypertrichosis which is generalized vellus hair growth distributed in a nonsexual pattern.

To meet the diagnostic criteria for hyperandrogenemia for PCOS and rule out other differential diagnoses, laboratory work is recommended (Table 6.3).