What is the approach for a Polycystic Ovary Syndrome (PCOS) workup?

PCOS Workup: Diagnostic Approach

The workup for PCOS requires establishing the Rotterdam criteria (2 of 3: hyperandrogenism, ovulatory dysfunction, or polycystic ovaries on ultrasound) while systematically excluding other causes of androgen excess and screening for metabolic complications. 1

Diagnostic Criteria

Apply the Rotterdam criteria: diagnose PCOS when 2 of the following 3 features are present: 1

• Clinical or biochemical hyperandrogenism (hirsutism, acne, male-pattern alopecia, or elevated androgens) 2, 1
• Ovulatory dysfunction (oligo-anovulation manifesting as irregular menstrual cycles) 3, 1
• Polycystic ovaries on ultrasound (≥12 follicles measuring 2-9 mm in diameter and/or ovarian volume >10 mL in at least one ovary) 3, 1

Initial Clinical Assessment

Measure BMI and waist circumference using ethnic-specific cutoffs (Asian, Hispanic, and South Asian populations require lower thresholds for cardiometabolic risk assessment) 4, 5

Document menstrual pattern specifics: cycle length, frequency of menses, duration of irregularity 2, 1

Assess hyperandrogenic features: hirsutism severity (Ferriman-Gallwey score if possible), acne distribution and severity, androgenic alopecia pattern 2, 6

Laboratory Evaluation

Exclude alternate androgen-excess disorders with the following tests: 1

• Total and free testosterone (or calculated free androgen index using SHBG) 1
• 17-hydroxyprogesterone (to exclude non-classic congenital adrenal hyperplasia; obtain early morning sample) 1
• Thyroid-stimulating hormone (TSH) (to exclude thyroid dysfunction) 1
• Prolactin (to exclude hyperprolactinemia) 1

Perform metabolic screening in all patients regardless of BMI (insulin resistance affects both lean and overweight women with PCOS): 5, 1

• Fasting glucose and hemoglobin A1c (or 2-hour oral glucose tolerance test for diabetes risk assessment) 1
• Lipid panel (total cholesterol, LDL, HDL, triglycerides) 2, 1
• Consider liver function tests (to screen for nonalcoholic fatty liver disease) 2

Imaging

Obtain transvaginal ultrasound (or transabdominal if virginal/adolescent) to assess ovarian morphology: count follicles and measure ovarian volume 3, 1

Additional Risk Screening

Screen for endometrial hyperplasia risk in patients with prolonged amenorrhea (>3 months) or abnormal uterine bleeding 1

Assess for obstructive sleep apnea using validated questionnaires (STOP-BANG), particularly in overweight patients, as this occurs more commonly in PCOS 2

Screen for mood disorders (depression, anxiety) and eating disorders, which are more prevalent in PCOS populations 2, 1

Evaluate cardiovascular risk factors: blood pressure measurement, family history of premature cardiovascular disease 2, 1

Special Diagnostic Considerations

In adolescents: diagnosis is problematic and requires caution; hyperandrogenism must be central to the presentation, as irregular cycles and polycystic ovaries can be normal developmental findings 1

In postmenopausal women: there is no consistent PCOS phenotype, making diagnosis unreliable in this population 1

Common Pitfalls to Avoid

Do not diagnose PCOS without excluding other causes of hyperandrogenism (Cushing syndrome, androgen-secreting tumors, thyroid disorders) 1

Do not skip metabolic screening in lean patients — insulin resistance is present irrespective of BMI and contributes to hyperandrogenism through effects on the pituitary, liver, and ovaries in all women with PCOS 5

Do not rely solely on ultrasound findings — polycystic ovaries alone are insufficient for diagnosis and occur in up to 20-30% of women without PCOS 6, 1

Recognize that ethnic-specific thresholds matter — Asian, Hispanic, and South Asian populations require lower BMI and waist circumference cutoffs for cardiometabolic risk stratification 4, 5