• Suspect polycystic ovary syndrome (PCOS) if the woman has one or more clinical features of:
• Infrequent or no ovulation — for example infertility, oligomenorrhoea, or amenorrhoea.
• Hyperandrogenism — for example hirsutism, acne vulgaris occurring after adolescence, or alopecia.
• Although it is not in the diagnostic criteria, women may have indirect evidence of insulin resistance, for example:
• Obesity, especially central obesity.
• Acanthosis nigricans. The skin is dry and rough, with grey-brown pigmentation; and is palpably thickened, and covered by a papillomatous elevation, giving it a velvety texture. The condition commonly affects the axillae, perineum, or extensor surfaces of the elbows and knuckles. When the neck is affected, there is often a thin necklace of warty fissures that can spread as a wide band.
• Increase the level of suspicion if there is a family history of PCOS.
• Exclude other conditions that have similar clinical presentations, as PCOS is a diagnosis of exclusion.

• The Rotterdam diagnostic criteria have been generally accepted and state that polycystic ovary syndrome (PCOS) should be diagnosed if two of three of the following criteria are present, as long as other causes of menstrual disturbance and hyperandrogenism are excluded [Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group, 2004; Ehrmann, 2005]:
• Infrequent or no ovulation (usually manifested as infrequent or no menstruation).
• Clinical or biochemical signs of hyperandrogenism (such as hirsutism, acne, or male pattern alopecia), or elevated levels of total or free testosterone.
• Polycystic ovaries on ultrasonography, defined as the presence of 12 or more follicles in at least one ovary, measuring 2–9 mm diameter, or increased ovarian volume (greater than 10 mL).
• Polycystic ovaries do not have to be present to make the diagnosis, and the finding of polycystic ovaries does not alone establish the diagnosis [Ehrmann, 2005].
• The Androgen Excess and PCOS Society Task Force has challenged the Rotterdam criteria [Azziz et al, 2006; Azziz et al, 2009].
• Only a minority of this task force considered that PCOS could exist without hyperandrogenism and suggested that PCOS should be defined by two criteria:
• The presence of hyperandrogenism (biochemical or clinical).
• Ovarian dysfunction (oligo- or anovulation or polycystic ovaries).
• However, the Rotterdam consensus definition provides a helpful framework, and too exclusive a definition would leave many women with PCOS who are at the milder end of the spectrum without a diagnosis [Balen et al, 2009].

• Measure the following to help diagnose polycystic ovary syndrome (PCOS).
• Total testosterone — this is normal to moderately elevated in women with PCOS.
• If the testosterone level is greater than 5 nanomol/L, test for 17-hydroxyprogesterone and seek specialist advice.
• Sex hormone-binding globulin — this is normal to low in women with PCOS. It provides a surrogate measurement of the degree of hyperinsulinaemia.
• Calculate the free androgen index (the normal range is usually less than 5, but this depends on local laboratories) — this is normal or elevated in women with PCOS. It provides an assessment of the amount of physiologically active testosterone present.
• To calculate the free androgen index, divide the total testosterone value (in nanomol/L x 100) by the sex hormone-binding globulin value (in nanomol/L).
• Measure the following to rule out other causes of oligomenorrhoea and amenorrhoea (such as premature ovarian failure, hypothyroidism, and hyperprolactinaemia):
• Luteinizing hormone and follicle-stimulating hormone — may be increased in women with premature ovarian failure and decreased in women with hypogonadotropic hypogonadism.
• Prolactin (normal range is less than 500 mU/L) — may be mildly elevated in women with PCOS.
• Thyroid-stimulating hormone (normal range 0.4–4.5 mU/L).
• Estradiol measurement is not recommended.
• Refer for pelvic ultrasonography (unless the diagnosis of PCOS is obvious on clinical and biochemical grounds):
• To look for the classic picture of polycystic ovaries (12 or more follicles in at least one ovary, measuring 2–9 mm in diameter) or increased ovarian volume (greater than 10 mL) in women who satisfy only one of the above two criteria.
• Exclude pregnancy and other diagnoses as appropriate — see Differential diagnosis.

Recommended blood tests

• These recommendations are based on guidelines from the Royal College of Obstetricians and Gynaecologists [RCOG, 2007].
• Total testosterone level is normal to moderately elevated in women with PCOS.
• High testosterone levels (greater than 5.0 nanomol/L) warrant investigation to exclude conditions such as late-onset congenital adrenal hyperplasia, Cushing's syndrome, or an androgen-secreting tumour [RCOG, 2007].
• A proportion of women with PCOS do not have an abnormality in their circulating androgens [Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group, 2004]. A study of 1741 women with PCOS found that only 29% had elevated serum testosterone (greater than 2.5 nanomol/L) [Balen et al, 1995].
• Combined oral contraceptives may normalize testosterone levels [Legro, 2007].
• Sex hormone-binding globulin (SHBG) provides a surrogate measure of the degree of hyperinsulinaemia.
• Insulin suppresses SHBG [Jayagopal et al, 2003; Balen et al, 2005].
• If the SHBG level is low despite an apparently normal total testosterone level, the amount of free testosterone (which is the bioactive form) may be increased, therefore elevating the free androgen index (FAI) [Balen et al, 2005].
• A small cross-sectional study of 12 women with PCOS found that serum SHBG levels were a useful marker for insulin resistance [Jayagopal et al, 2003].
• The FAI (or free testosterone) measurement is the most sensitive method of assessing hyperandrogenaemia [Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group, 2004]. If the SHBG and total testosterone levels are known, the FAI can be calculated. The FAI provides a simple assessment of the amount of physiologically-active testosterone present. Free testosterone may reflect the combined effects of:
• Insulin resistance (increased insulin level and decreased SHBG level).
• Ovarian and adrenal hyperandrogenism (increased total circulating testosterone) [Legro, 1998].
• Thyroid-stimulating hormone and prolactin.
• Prolactin levels may be normal or mildly elevated in PCOS [Balen et al, 2005]. About 10–25% of women with PCOS have mildly elevated prolactin levels [Practice Committee of the American Society for Reproductive Medicine, 2008].
• Although thyroid-stimulating hormone is a useful screening test, the incidence of thyroid dysfunction among women with hyperandrogenism is no higher than that in women without hyperandrogenism who are of reproductive age [Balen et al, 2005].

Tests not recommended for the diagnosis of PCOS but essential for the diagnosis of other conditions that may present with amenorrhoea

• Luteinizing hormone (LH)/follicle-stimulating hormone (FSH) ratios are no longer considered useful in diagnosing PCOS because of their inconsistency [RCOG, 2007].
• The FSH level is normal in PCOS [Azziz et al, 2009].
• The LH level may be moderately elevated in PCOS [Azziz et al, 2009]. A single blood sample may fail to detect an increased LH level because of the pulsatile nature of gonadotrophin release [Dunaif, 1997; McIver et al, 1997]. A study of 1741 women with polycystic ovaries and other features of PCOS found that 39% had increased LH (greater than 10 IU/L) [Balen et al, 1995].
• Measurement of FSH and LH are essential in the diagnosis of other conditions that may present with amenorrhoea [Balen et al, 2005].
• Estradiol measurement is not recommended, as levels tend to fluctuate, and can be normal or low in both PCOS and hypothalamic amenorrhoea [Practice Committee of the American Society for Reproductive Medicine, 2008]. Estrogenization may be confirmed by endometrial assessment [Balen et al, 2005].

Pelvic ultrasonography

• The recommendation to do pelvic ultrasonography to assess ovarian morphology is based on expert advice in a textbook [Balen et al, 2005].
• Polycystic ovaries do not have to be present to make the diagnosis, and the finding of polycystic ovaries does not alone establish the diagnosis. In some women, the combination of irregular menses and biochemical hyperandrogenism may obviate the need for pelvic ultrasonography if there is confidence in the diagnosis.

• The diagnosis of polycystic ovary syndrome involves the exclusion of all of the following disorders, which may have a similar clinical presentation:
• Simple obesity.
• Primary hypothyroidism.
• Premature ovarian failure.
• Hyperprolactinaemia.
• Non-classic congenital adrenal hyperplasia.
• Cushing's syndrome.
• Androgen-secreting neoplasm.
• Hypogonadotropic hypogonadism (that is central origin of ovarian dysfunction).
• Hyperandrogenic-insulin resistant-acanthosis nigricans (HAIRAN) syndrome.
• High-dose exogenous androgens.
• Acromegaly.
• Also consider drug-related conditions.
• The following drugs may cause hirsutism:
• Androgenic drugs, including testosterone, danazol, gestrinone, adrenocorticotropic hormone, high-dose corticosteroids, androgenic progestogens in oral contraceptives, and anabolic steroids.
• Non-androgenic drugs, including ciclosporin, diazoxide, minoxidil, and phenytoin; rarely, carbamazepine, sodium valproate, and acetazolamide.
• The following drugs may cause hypertrichosis: ciclosporin, diazoxide, minoxidil, and phenytoin.

[Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group, 2004; Ehrmann, 2005; Aronson, 2006; Micromedex, 2009]