PCOS Diagnosis Understanding Your Lab Tests for PCOS By Nicole Galan, RN facebook twitter linkedin Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book." Learn about our editorial process Nicole Galan, RN Medically reviewed by Medically reviewed by Lindsey Waldman, MD, RD on November 06, 2019 linkedin Lindsey Waldman, MD, RD, is a board-certified pediatrician and pediatric endocrinologist. Learn about our Medical Review Board Lindsey Waldman, MD, RD Updated on November 19, 2019 Print If you have polycystic ovary syndrome (PCOS), you may be experiencing any number of symptoms, like irregular menstrual cycles or signs of high androgen levels, including acne and abnormal hair growth (hirsutism). If you stop menstruating or your doctor suspects you have PCOS, a number of tests may be ordered to determine whether PCOS is the cause or some other condition is involved, such as an underactive thyroid gland (hypothyroidism). Unlike other medical conditions, the diagnosis of PCOS is based largely on a process of elimination. There is no single blood test that can diagnose the disease. Rather, the doctor will accumulate evidence from blood works—along with imaging studies and a pelvic exam—to help support the diagnosis of PCOS. 9 Signs That You Have PCOS Westend61 / Getty Images Diagnostic Blood Tests If you've missed your period or have stopped menstruating, the first test your doctor will likely do is a pregnancy test to ensure that pregnancy is not the cause. If the test is negative, your doctor will move forward with other blood works. FSH/LH Blood Test Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are produced by the pituitary gland, a pea-sized organ located at the base of your brain. FSH stimulates the growth of an egg follicle within the ovary, while the surge of LH triggers the release of the egg during ovulation. In the past, the diagnosis of PCOS was made based on an LH-to-FSH ratio greater than 3-to-1 (3:1). This is not the case anymore since many women with PCOS have persistently elevated LH levels throughout their entire cycle and otherwise normal hormone levels. Most women with PCOS will have FSH levels that are lower than the LHR levels. So, while the testing of FSH and LH can help support the diagnosis of PCOS, it cannot confirm it. Also, if your FSH is elevated, it may be an indication of an unrelated condition called primary ovarian insufficiency. 17-Hydroxyprogesterone Test This blood test, also known as 17-OHP, is used to detect a hormone produced by the adrenal glands that is involved in the production of the stress hormone cortisol. The test is used to determine the presence of late-onset congenital adrenal hyperplasia, another medical condition that can mimic the symptoms of PCOS. DHEA/Testosterone Blood Test Dehydroepiandrosterone (DHEA) and testosterone belong to a class of hormones known as androgens (a.k.a. male hormones). They are responsible for secondary male sex characteristics and are the cause of many of the symptoms of PCOS, including acne, hirsutism, female-pattern baldness, and menstrual irregularities. While the elevation of testosterone is typical in women with PCOS, it is possible to have a spontaneous outbreak of acne and hirsutism with normal androgen levels and still be diagnosed PCOS. As such, androgen irregularities are a guide by which PCOs is diagnosed, but they aren't a hard-and-fast rule. Rarely, abnormally elevated testosterone levels could be a sign of an androgen-secreting tumor of the ovary. Likewise, high DHEA levels could be a sign of an androgen-secreting tumor of the adrenal glands. 6 Things No One Tells You about PCOS Thyroid Function Tests This panel of blood tests is used to rule out thyroid dysfunction as a cause of your menstrual irregularity. Thyroid-stimulating hormone (TSH) is also secreted by the pituitary gland and regulates the release of the two thyroid hormones, called triiodothyronine (T3) and thyroxine (T4). These two hormones regulate basic metabolic function. Low levels of either could produce menstrual changes similar to those experienced in women with PCOS. Prolactin Test Prolactin is a hormone secreted by the pituitary gland whose primary role is promoting lactation in women. Elevated values of this hormone (referred to as hyperprolactinemia) can cause irregular menstruation (oligomenorrhea) or a total lack of menstruation (amenorrhea). If levels of prolactin in your blood are elevated, your doctor will test your thyroid function since untreated hypothyroidism can also cause elevated prolactin. Your doctor will also likely order a magnetic resonance imaging (MRI) scan of the pituitary gland to see whether a tumor called a prolactinoma is involved. The Facts About PCOS and Infertility Blood Tests for Co-Occurring Conditions If you are diagnosed with PCOS, your doctor will want to investigate whether you have type 2 diabetes and high cholesterol both of which are common in women with PCOS. Oral Glucose Tolerance Test An oral glucose tolerance test (OGTT) measures your response to sugar. Insulin is the major hormone that regulates blood sugar (glucose) and the way it is metabolized for energy. For the OGTT, you will be given a very sweet, sugary solution to drink. Blood tests will be drawn before the test and one and two hours after. Urine samples may be collected as well. In people without diabetes, the blood sugar should return to normal within two hours. If not, the test may be indicative of prediabetes or diabetes. Lipid Panel A cholesterol test, also referred to as a lipid panel, measures all of the key values associated with high cholesterol, including total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and another type of lipid known as a triglyceride. Women with PCOS often high cholesterol, which can increase the risk of heart disease and diabetes. Some studies suggest that up to 70% of women with PCOS some degree of elevated cholesterol and/or triglycerides. A Word From Verywell While it may seem like your doctor is ordering a lot of blood tests to diagnose PCOS, this is perfectly normal and no cause for alarm. The more tests your doctor performs to confirm the disorder—and rule out others—the better equipped they will be in dispensing the correct treatment. How PCOS Is Treated Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Sheehan MT. Polycystic ovarian syndrome: diagnosis and management. Clin Med Res. 2004;2(1):13–27. doi:10.3121/cmr.2.1.13 Saadia Z. Follicle stimulating hormone (LH: FSH) ratio in polycystic ovary syndrome (PCOS) - obese vs. non- obese women. Med Arch. 2020 Aug;74(4):289–93. doi:10.5455/medarh.2020.74.289-293 Raju GA, Chavan R, Deenadayal M, et al. Luteinizing hormone and follicle stimulating hormone synergy: A review of role in controlled ovarian hyper-stimulation. J Hum Reprod Sci. 2013;6(4):227–234. doi:10.4103/0974-1208.126285 Macut D, Ilic D, Jovanovic AM, Bjekic-Macut J. Androgen-secreting ovarian tumors. Front Horm Res. 2019;53:100-7. doi:10.1159/000494906 Christodoulaki C, Trakakis E, Pergialiotis V, et al. Dehydroepiandrosterone-Sulfate, Insulin Resistance and Ovarian Volume Estimation in Patients With Polycystic Ovarian Syndrome. J Family Reprod Health. 2017;11(1):24–29. Ganvir S, Sahasrabuddhe A, Pitale S. Thyroid function tests in polycystic ovarian syndrome. Nat J Physiol Pharm Pharmacol. 2017;7(3):269-72. Szosland K, Pawlowicz P, Lewiński A. Prolactin secretion in polycystic ovary syndrome (PCOS). Neuro Endocrinol Lett. 2015;36(1):53-8 Ortiz-Flores AE, Luque-Ramirez M, Fernandez-Duran E, Alvarez-Blasco F, Escobar-Morreale HF. Diagnosis of disorders of glucose tolerance in women with polycystic ovary syndrome (PCOS) at a tertiary care center: fasting plasma glucose or oral glucose tolerance test?. Metabolism. 2019 Apr;93:86-92. doi:10.1016/j.metabol.2019.01.015 Kim JJ, Choi YM. Dyslipidemia in women with polycystic ovarian syndrome. Obstet Gynecol Sci. 2013; 56: 137-42. doi:10.5468/ogs.2013.56.3.137 Additional Reading American Association for Clinical Chemistry. Polycystic Ovary Syndrome. Lab Tests Online. Updated November 28, 2017. Mayo Clinic Staff. Polycystic Ovary Syndrome (PCOS). Mayo Clinic. Updated August 29, 2017. Sirmans SM, Pate KA. Epidemiology, Diagnosis, and Management of Polycystic Ovary Syndrome. Clinical Epidemiology. 2014;6:1-13. doi:10.2147/CLEP.S37559.