There is no single test to diagnose polycystic ovarian syndrome (PCOS), which makes diagnosis difficult. However, the American Society for Reproductive Medicine (ASRM) and European Society for Human Reproduction and Embryology (ESHRE) have agreed on guidelines for PCOS diagnosis. To be diagnosed with PCOS, a woman must exhibit two of the following:

• Irregular or absent ovulation
  
  
• Elevated levels of androgens (male hormones such as testosterone)
  
  
• Enlarged ovaries containing 12 or more follicles each (polycystic ovaries) diagnosed by ultrasound

A physician will first evaluate the physical symptoms and obtain a woman’s medical history, including her menstrual history and family history. This is followed by a physical examination, including a pelvic examination, typically conducted by an obstetrician-gynecologist (ObGyn). 

Other tests may be performed to either aid in the diagnosis of PCOS or to rule out other conditions that may cause similar symptoms. These may include:

• Blood tests. Laboratory examinations of blood samples to measure blood levels of the following:
  
  
• • Thyroid hormone. Symptoms of low thyroid function are similar to those of PCOS.
    
    
  • Prolactin hormone. Excess levels of this hormone stimulate milk production and often result in irregular or absent periods, which is also a symptom of hyperprolactinemia.
    
    
  • Male hormones (androgens). Excessive levels of these hormones often cause “male-like” characteristics, such as excess body and/or facial hair (hirsutism).
    
    
  • Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. A high ratio of LH to FSH (typically three to one) is indicative of PCOS.
    
    
  • Insulin and glucose (blood sugar) levels (usually a morning fasting level is required). Excess levels of these are also indicative of insulin resistance or type 2 diabetes.
    
    
  • Lipids (cholesterol and triglyceride levels). Excessive levels of these may result in high blood pressure.
    
    
  The best time to be tested for PCOS is in the morning shortly after the start of the menstrual cycle. Therefore, a physician may prescribe medication to induce menstruation. Birth control medications might make the tests difficult to interpret because they affect hormonal imbalance. The patient may be referred to a specialist for interpretation of the blood test results, such as an endocrinologist or reproductive endocrinologist.
  
  
• Ultrasound. An imaging test that uses sound waves to produce a picture of the body’s organs and structures, the woman may receive a pelvic ultrasound or transvaginal ultrasound. These tests may be used to check for the presence of the characteristic images that depict polycystic ovaries or to determine if the lining of the uterus has thickened. Although ultrasounds can help confirm a PCOS diagnosis, they are not always accurate because not all women that have cysts have PCOS and not all women with PCOS have polycystic ovaries. The images produced by the ultrasound should be examined by a physician experienced with their interpretations.
  
  
• Endometrial biopsy. The removal of a tissue sample from the uterine lining for laboratory analysis. It may be used to detect any precancerous and cancerous conditions that can cause abnormal bleeding.

Because PCOS encompasses a broad spectrum of symptoms, it is considered a diagnosis of exclusion. This means that physicians will first rule out other conditions with similar symptoms such as:

• High prolactin hormone levels (hyperprolactinemia)
  
  
• Excess adrenal hormones
  
  
• Cushing syndrome (a disorder of overactivity of the adrenal gland)
  
  
• Androgen-secreting tumors in the ovaries
  
  
• Thyroid problems (e.g., autoimmune thyroiditis, hypothyroidism, hyperthyroidism)
  
  
• Eating disorders

If a woman is diagnosed with PCOS, she should be tested and treated for other complications that may be associated with it, such as insulin resistance, heart disease, high blood pressure, hirsutism, type 2 diabetes and uterine cancer.