Polycystic Ovary Syndrome (PCOS) is a common hormonal disorder among women of reproductive age. Diagnosing PCOS typically involves a combination of clinical evaluation, imaging studies, and blood tests to assess hormone levels and rule out other conditions. Here are the key blood tests often used in the evaluation of PCOS:

1. Total and Free Testosterone

  • Purpose: Elevated levels of testosterone are a hallmark of PCOS and are associated with symptoms such as hirsutism, acne, and male-pattern baldness.
  • Normal Range: Varies by lab, but typically total testosterone levels are between 15 and 70 ng/dL for women.

2. Sex Hormone-Binding Globulin (SHBG)

  • Purpose: SHBG binds to sex hormones, including testosterone. Low levels of SHBG are often seen in PCOS and can lead to higher levels of free testosterone.
  • Normal Range: Typically 18-144 nmol/L for women.

3. Androstenedione

  • Purpose: A precursor to both testosterone and estrogen, androstenedione levels are often elevated in women with PCOS.
  • Normal Range: 0.7 to 3.1 ng/mL.

4. Dehydroepiandrosterone Sulfate (DHEA-S)

  • Purpose: An adrenal androgen that may be elevated in PCOS, contributing to symptoms of hyperandrogenism.
  • Normal Range: Varies by age, typically 35-430 µg/dL for women.

5. Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)

  • Purpose: The LH to FSH ratio is often higher in women with PCOS (typically >2:1). This imbalance can disrupt ovulation.
  • Normal Range: LH: 1.9-12.5 IU/L, FSH: 2.5-10.2 IU/L during the follicular phase.

6. Prolactin

  • Purpose: Elevated prolactin levels can cause irregular menstrual cycles and should be ruled out as a cause of menstrual irregularities.
  • Normal Range: Typically less than 25 ng/mL for non-pregnant women.

7. Thyroid-Stimulating Hormone (TSH)

  • Purpose: To rule out thyroid dysfunction, which can mimic or exacerbate symptoms of PCOS.
  • Normal Range: 0.4 to 4.0 mIU/L.

8. Anti-Mullerian Hormone (AMH)

  • Purpose: AMH levels are often elevated in PCOS and reflect the number of antral follicles (ovarian reserve).
  • Normal Range: 1-10 ng/mL, but levels above 4.5 ng/mL are often indicative of PCOS.

9. Fasting Glucose and Insulin Levels

  • Purpose: To assess insulin resistance, which is common in PCOS and associated with an increased risk of type 2 diabetes.
  • Normal Range:
    • Fasting Glucose: 70-99 mg/dL
    • Fasting Insulin: 2.6-24.9 µIU/mL

10. Lipid Profile

  • Purpose: To evaluate cardiovascular risk factors, as women with PCOS often have dyslipidemia.
  • Components: Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

Diagnostic Criteria for PCOS:

According to the Rotterdam criteria, a diagnosis of PCOS requires two out of the following three criteria:

  1. Irregular or Absent Menstrual Periods: Oligomenorrhea or amenorrhea.
  2. Hyperandrogenism: Clinical signs (e.g., hirsutism, acne) and/or biochemical evidence (elevated androgen levels).
  3. Polycystic Ovaries: Visible on ultrasound, typically showing 12 or more follicles in each ovary or increased ovarian volume.

Additional Considerations:

  • Clinical Evaluation: Detailed medical history, physical examination, and assessment of symptoms.
  • Pelvic Ultrasound: To visualize ovarian morphology and assess for polycystic ovaries.

Preparation for Blood Tests:

  • Timing: Some hormone tests are best performed during the early follicular phase (days 2-5) of the menstrual cycle.
  • Fasting: Required for glucose and lipid profile tests.

Follow-Up and Management:

  • Lifestyle Changes: Weight management, diet, and exercise can improve symptoms and reduce risks.
  • Medications: May include hormonal contraceptives, anti-androgens, insulin-sensitizing agents (e.g., metformin), and fertility treatments if conception is desired.
  • Monitoring: Regular follow-up to monitor symptoms, metabolic parameters, and adjust treatment as needed.

Consulting with a healthcare provider, particularly an endocrinologist or gynaecologist, is essential for accurate diagnosis and personalized management of PCOS.