What laboratory tests are necessary to diagnose Polycystic Ovary Syndrome (PCOS)?

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From the Guidelines

To work up for Polycystic Ovary Syndrome (PCOS), the most essential laboratory tests include LH, FSH, prolactin, testosterone, androstenedione, DHEAS, glucose/insulin, and pelvic ultrasound, as these tests help establish the diagnosis of PCOS by confirming hyperandrogenism, evaluating ovarian function, and assessing metabolic health. When evaluating a patient for PCOS, it is crucial to consider the diagnostic criteria, which include ovulatory dysfunction, clinical or biochemical hyperandrogenism, and/or polycystic ovary morphology (PCOM) on ultrasound 1. The measurement of androgens, such as total testosterone, free testosterone, and androstenedione, is critical in diagnosing biochemical hyperandrogenism, which is present in 75% of PCOS cases 1. Additionally, assessing insulin resistance through fasting glucose, hemoglobin A1c, and fasting insulin levels is important, as PCOS is associated with insulin resistance and increased risk of type 2 diabetes and cardiovascular disease 1. Other tests, such as prolactin, thyroid-stimulating hormone (TSH), and a lipid panel, may also be valuable in ruling out other endocrine disorders and assessing metabolic health. It is essential to note that the diagnostic accuracy of specific androgen measurement methods can be challenging, and the choice of test should be based on the most reliable and accurate approach for assessing PCOS-related biochemical hyperandrogenism 1. In clinical practice, a combination of these tests, along with a thorough medical history and physical examination, can help establish an accurate diagnosis of PCOS and guide treatment decisions. Some key points to consider when ordering labs for PCOS include:

  • Measuring LH and FSH levels to evaluate ovarian function
  • Assessing androgen levels, such as testosterone and androstenedione, to confirm hyperandrogenism
  • Evaluating insulin resistance through fasting glucose and insulin levels
  • Performing a pelvic ultrasound to assess for polycystic ovary morphology
  • Ruling out other endocrine disorders, such as hypothyroidism or hyperprolactinemia, through measurement of TSH and prolactin levels.

From the Research

Diagnostic Criteria for PCOS

To diagnose Polycystic Ovary Syndrome (PCOS), the following criteria are used:

  • Presence of two of the following criteria: androgen excess, ovulatory dysfunction, or polycystic ovaries, as suggested by the Rotterdam criteria 2
  • Evaluation of women with PCOS should exclude alternate androgen-excess disorders and risk factors for endometrial cancer, mood disorders, obstructive sleep apnea, diabetes, and cardiovascular disease 2

Laboratory Tests for PCOS

The following laboratory tests may be used to work up for PCOS:

  • Hormone level tests to check for androgen excess
  • Tests to rule out other causes of infertility or menstrual irregularities
  • Fasting glucose and lipid profiles to assess the risk of metabolic and cardiovascular disease 2, 3
  • Thyroid function tests to rule out thyroid disorders

Additional Evaluations

Additional evaluations that may be performed include:

  • Pelvic exam to check for any abnormalities in the reproductive organs
  • Ultrasound to check for polycystic ovaries
  • Mental health screening to assess the risk of mood disorders 3
  • Sleep study to assess the risk of obstructive sleep apnea 2

Special Considerations

Special considerations should be taken into account when diagnosing PCOS in certain populations, such as:

  • Adolescents, where hyperandrogenism is central to the presentation 2
  • Menopausal women, where there is no consistent phenotype 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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