What is a good hormonal lab panel for women with Polycystic Ovary Syndrome (PCOS)?

Comprehensive Hormonal Lab Panel for Women with PCOS

A comprehensive hormonal lab panel for women with PCOS should include testosterone or bioavailable/free testosterone, thyroid-stimulating hormone (TSH), prolactin, a two-hour oral glucose tolerance test, and a fasting lipid profile to assess for metabolic complications and rule out other causes of androgen excess. 1, 2

Core Hormonal Tests

• Androgen Assessment:

  • Total testosterone or bioavailable/free testosterone (preferred) - most frequently abnormal biochemical marker (70% of PCOS cases) 1, 3
  • Sex hormone-binding globulin (SHBG) - often decreased in PCOS and correlates negatively with body mass index 2, 3
  • Free androgen index (FAI) - calculated from total testosterone and SHBG 2
  • Dehydroepiandrosterone sulfate (DHEA-S) - to assess for adrenal androgen excess 1, 2
  • Androstenedione - abnormal in approximately 53% of PCOS cases 3

• Gonadotropin Assessment:

  • Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) - to evaluate for elevated LH/FSH ratio 1, 2
  • Note: LH/FSH ratio has limited sensitivity (41-44%) and should not be used as the sole diagnostic criterion 3

Tests to Rule Out Other Causes of Androgen Excess

• Thyroid function: TSH to exclude thyroid disorders 1, 2
• Prolactin level: To rule out hyperprolactinemia 1, 2
• 17-hydroxyprogesterone: To exclude non-classic congenital adrenal hyperplasia 4
• Cortisol studies: Consider if clinical features of Cushing's syndrome are present 1

Metabolic Assessment

• Glucose metabolism:

  • Fasting glucose 1
  • Two-hour oral glucose tolerance test with 75g glucose load - recommended for all women with PCOS due to increased risk of type 2 diabetes 1, 2
  • Fasting insulin - to calculate HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) 5

• Lipid profile:

  • Total cholesterol 1, 2
  • LDL cholesterol 1, 2
  • HDL cholesterol 1, 2
  • Triglycerides 1, 2

Emerging Biomarkers

• Anti-Müllerian hormone (AMH):
  • Currently not recommended as a single diagnostic test for PCOS 1, 2
  • May be useful with improved standardization of assays and established cut-off levels 1

Clinical Pitfalls to Avoid

• Timing of testing: Hormonal evaluations should ideally be performed during the early follicular phase (days 2-5) of the menstrual cycle for accurate assessment 3
• Assay variability: Be aware that absolute gonadotropin values can differ significantly between different assay methods 3
• Over-reliance on LH/FSH ratio: This has low sensitivity and should not be used as the sole diagnostic criterion 3
• Failure to assess metabolic parameters: All women with PCOS should be screened for metabolic abnormalities, particularly those who are overweight or obese 1, 5
• Missing other causes of hyperandrogenism: Always consider differential diagnoses such as Cushing's syndrome, androgen-secreting tumors, and non-classic congenital adrenal hyperplasia 1

Testing Algorithm

1. Initial screening:

   • Total testosterone or bioavailable/free testosterone
   • TSH
   • Prolactin
   • Fasting glucose and lipid profile 1, 2

2. If initial screening suggests PCOS:

   • Complete the full hormonal panel (SHBG, DHEA-S, androstenedione)
   • Perform two-hour oral glucose tolerance test 1

3. If clinical features suggest other disorders:

   • Add 17-hydroxyprogesterone (if congenital adrenal hyperplasia suspected)
   • Add cortisol studies (if Cushing's syndrome suspected) 1, 4

By following this comprehensive approach to hormonal testing in women with PCOS, clinicians can accurately diagnose the condition, rule out other causes of hyperandrogenism, and identify metabolic complications that may impact long-term health outcomes.