Standard diagnostic assessments
History-taking, specifically for menstrual pattern, obesity, hirsutism, and the absence of breast development. A clinical prediction rule found that these four questions can diagnose PCOS with a sensitivity of 77.1% (95% confidence interval [CI] 62.7%88.0%) and a specificity of 93.8% (95% CI 82.8%98.7%).[16]
Gynecologic ultrasonography, specifically looking for small ovarian follicles. These are believed to be the result of disturbed ovarian function with failed ovulation, reflected by the infrequent or absent menstruation that is typical of the condition. In a normal menstrual cycle, one egg is released from a dominant follicle - essentially a cyst that bursts to release the egg. After ovulation the follicle remnant is transformed into a progesterone-producing corpus luteum, which shrinks and disappears after approximately 1214 days. In PCOS, there is a so called "follicular arrest", i.e., several follicles develop to a size of 57 mm, but not further. No single follicle reaches the preovulatory size (16 mm or more). According to the Rotterdam criteria, 12 or more small follicles should be seen in an ovary on ultrasound examination. The follicles may be oriented in the periphery, giving the appearance of a 'string of pearls'. The numerous follicles contribute to the increased size of the ovaries, that is, 1.5 to 3 times larger than normal.[citation needed]
Laparoscopic examination may reveal a thickened, smooth, pearl-white outer surface of the ovary. (This would usually be an incidental finding if laparoscopy were performed for some other reason, as it would not be routine to examine the ovaries in this way to confirm a diagnosis of PCOS).[citation needed]
Serum (blood) levels of androgens (male hormones), including androstenedione and testosterone may be elevated.[7] Dehydroepiandrosterone sulfate levels above 700mcg/dL are highly suggestive of adrenal dysfunction because DHEA-S is made exclusively by the adrenal glands. [17] The free testosterone level is thought to be the best measure,[18] with ~60% of PCOS patients demonstrating supranormal levels.[14] The Free androgen index of the ratio of testosterone to sex hormone-binding globulin (SHBG) is high[7] and is meant to be a predictor of free testosterone, but is a poor parameter for this and is no better than testosterone alone as a marker for PCOS,[19] possibly because FAI is correlated with the degree of obesity.[20]
Some other blood tests are suggestive but not diagnostic. The ratio of LH (Luteinizing hormone) to FSH (Follicle stimulating hormone) is greater than 1:1, as tested on Day 3 of the menstrual cycle. The pattern is not very specific and was present in less than 50% in one study.[21] There are often low levels of sex hormone binding globulin, particularly among obese or overweight women.[citation needed]