Diagnostic Workup for Polycystic Ovary Syndrome (PCOS)

Diagnostic Criteria

The diagnostic workup for PCOS should include assessment of hyperandrogenism, ovulatory dysfunction, and polycystic ovary morphology, with total testosterone and free testosterone as first-line laboratory tests for biochemical hyperandrogenism 1, 2
PCOS is diagnosed according to the Rotterdam criteria, requiring at least two of the following three findings: hyperandrogenism, ovulatory dysfunction, and polycystic ovary morphology on ultrasound 2

Total testosterone has a sensitivity of 74% and specificity of 86% for diagnosing PCOS 1, 3
Free testosterone should be assessed by equilibrium dialysis or calculated using free androgen index (FAI) 2
Calculated free testosterone has a sensitivity of 89% and specificity of 83% for diagnosing PCOS 3
Free androgen index has a sensitivity of 78% and specificity of 85% for diagnosing PCOS 3
Androstenedione has a sensitivity of 75% and specificity of 71% for diagnosing PCOS 3, 4
Dehydroepiandrosterone sulfate has a sensitivity of 75% and specificity of 67% for diagnosing PCOS 3, 4

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the preferred method for androgen measurement due to superior accuracy 2, 3
Direct immunoassays have lower sensitivity and specificity compared to LC-MS/MS 3

Relying solely on direct immunoassay methods for testosterone measurement can lead to inaccurate diagnoses 2

The Endocrine Society recommends that ultrasound should not be used as a primary diagnostic criterion in adolescents <8 years post-menarche due to high false-positive rates from normal multi-follicular ovaries in this age group, however, biochemical hyperandrogenism (elevated free testosterone and FAI) provides the necessary confirmation for PCOS diagnosis in patients with polycystic ovaries on ultrasound and clinical features of the syndrome 5