From the Guidelines
The diagnosis of Polycystic Ovary Syndrome (PCOS) should include total testosterone (TT), free testosterone (FT), and free androgen index (FAI) as the first-line laboratory tests to assess biochemical hyperandrogenism, as recommended by the 2023 International PCOS Guidelines 1. The selection of these tests is based on their high diagnostic accuracy for biochemical hyperandrogenism, a key feature of PCOS. According to a systematic review and diagnostic meta-analysis published in Human Reproduction Update in 2025, TT, FT, and FAI have been found to have high sensitivity and specificity for diagnosing PCOS 1. The use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) is recommended for measuring TT, FT, and other androgens due to its high accuracy compared to direct immunoassay methods 1. If TT or FT is not elevated, measuring androstenedione (A4) and dehydroepiandrosterone sulfate (DHEAS) could be considered, noting their poorer specificity 1. Key points to consider in the workup for PCOS diagnosis include:
- Using TT, FT, and FAI as first-line tests
- Utilizing LC-MS/MS for androgen measurement when possible
- Considering A4 and DHEAS if initial tests are not elevated
- Ruling out other endocrine disorders through additional tests such as 17-hydroxyprogesterone, cortisol levels, or dexamethasone suppression tests as necessary.
From the Research
Lab Tests for PCOS Diagnosis
The diagnosis of Polycystic Ovary Syndrome (PCOS) involves a combination of clinical, laboratory, and imaging evaluations. The following lab tests are recommended for the diagnosis of PCOS:
- Hormone levels:
- Other tests:
Diagnostic Criteria
The diagnosis of PCOS is based on the presence of at least two of the following three criteria:
- Clinical and/or biochemical signs of hyperandrogenism
- Oligoovulation or anovulation
- Polycystic ovaries on ultrasound 5, 4 The Rotterdam criteria and the Japan Society of Obstetrics and Gynecology (JSOG) criteria are commonly used for the diagnosis of PCOS 5, 3.
Laboratory Evaluation
Laboratory tests are essential for the diagnosis of PCOS, as they help to confirm the presence of hyperandrogenism and rule out other conditions that may mimic PCOS. The laboratory evaluation should include:
- Hormone level measurements: LH, FSH, TT, PRL, and AMH 2
- Glucose and insulin level measurements: to assess insulin resistance 4
- Lipid profile: to evaluate cardiovascular risk 4
Cut-off Values
The cut-off values for LH and the LH/FSH ratio may vary depending on the assay system used. Studies have reported the following cut-off values: