From the Guidelines
The diagnosis of Polycystic Ovary Syndrome (PCOS) is primarily based on laboratory tests that assess hormone levels, including total and free testosterone, sex hormone-binding globulin (SHBG), androstenedione, and DHEAS, as well as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to evaluate androgen excess and ovarian function 1. To diagnose PCOS, the following laboratory tests are recommended:
- Hormone level assessments: total and free testosterone, SHBG, androstenedione, and DHEAS to evaluate androgen excess
- LH and FSH to assess ovarian function, with an LH:FSH ratio often elevated in PCOS
- Thyroid function tests (TSH, free T4) and prolactin levels to rule out other conditions that may mimic PCOS symptoms
- Metabolic evaluations: fasting glucose, hemoglobin A1C, and a lipid panel to assess for insulin resistance and cardiovascular risk factors
- A 2-hour oral glucose tolerance test may be recommended to detect impaired glucose tolerance These tests help establish the diagnosis based on the Rotterdam criteria, which require two of three features: oligo/anovulation, clinical or biochemical hyperandrogenism, and polycystic ovaries on ultrasound, as supported by the most recent evidence 1. It is essential to note that the diagnosis of PCOS should be based on the most recent and accurate laboratory tests, and the interpretation of the results should consider the individual patient's characteristics, such as age, weight, and medication use, as highlighted in the study by 1. In clinical practice, the diagnosis of PCOS is often challenging due to the variability in symptoms and laboratory results, and the lack of consensus in reference ranges for androgen measurements, as discussed in the study by 1. However, by using the recommended laboratory tests and considering the individual patient's characteristics, clinicians can establish an accurate diagnosis and provide timely management of symptoms and prevention of long-term complications like diabetes and cardiovascular disease, as emphasized by the study by 1.
From the Research
Laboratory Tests for Diagnosing Polycystic Ovary Syndrome (PCOS)
The diagnosis of PCOS involves a combination of clinical, laboratory, and imaging evaluations. The following laboratory tests are used to diagnose PCOS:
- Fasting blood glucose 2, 3
- Oral glucose tolerance test (OGTT) 2, 3
- Hemoglobin A1C (HbA1C) 2, 3, 4
- Lipid profile 3, 5, 4
- Thyroid-stimulating hormone (TSH) 5
- Free testosterone (FT) 5, 6
- Luteinizing hormone (LH) 5, 6, 4
- Follicle-stimulating hormone (FSH) 5, 6, 4
- Prolactin 5
- 17-hydroxyprogesterone 6
- Anti-Müllerian hormone (AMH) 6
- Sex hormone-binding globulin (SHBG) 6, 4
Frequency of Laboratory Tests
The frequency of laboratory tests for PCOS diagnosis and monitoring varies:
- Fasting blood glucose, random glucose, and HbA1C are often checked before diagnosis, but less frequently after diagnosis 4
- Endocrine testing (oestradiol, LH, FSH, testosterone, SHBG) tends to peak in the weeks before diagnosis 4
- Plasma glucose testing is performed more evenly over time, as is serum cholesterol testing 4
Imaging Tests
Imaging tests, such as pelvic ultrasound, are also used to support the diagnosis of PCOS:
- Pelvic ultrasound scans are often performed in the month immediately prior to diagnosis 4