What are the steps for a Polycystic Ovary Syndrome (PCOS) workup?

PCOS Workup

Diagnose PCOS using the Rotterdam criteria—requiring at least two of three features: hyperandrogenism, ovulatory dysfunction, or polycystic ovarian morphology—after systematically excluding other causes of androgen excess through targeted laboratory testing and clinical assessment. 1

Initial Clinical Assessment

History Components

Document the following specific elements:

• Menstrual pattern: Onset and duration of oligomenorrhea or amenorrhea 2
• Androgen excess signs: Timing and progression of hirsutism, acne, or alopecia 2
• Medication review: Screen for exogenous androgen use 2
• Lifestyle factors: Diet, exercise habits, alcohol consumption, smoking status 2
• Family history: Cardiovascular disease, diabetes, and reproductive disorders 2

Physical Examination Findings

Systematically assess for:

• Hyperandrogenism signs: Acne distribution, male-pattern balding, clitoromegaly 1
• Hirsutism: Document body hair distribution patterns 1
• Insulin resistance markers: Acanthosis nigricans on neck, axillae, beneath breasts, or vulva 2, 1
• Body habitus: Calculate BMI and waist-hip ratio 2
• Ovarian enlargement: Pelvic examination findings 2
• Cushing's features: Buffalo hump, moon facies, hypertension, abdominal striae, centripetal fat distribution, easy bruising, proximal myopathy 2

Laboratory Workup

Essential Hormonal Testing

Order these tests to confirm PCOS features and exclude mimicking disorders:

• Testosterone: Total or free testosterone using mass spectrometry (superior specificity over immunoassays) to document hyperandrogenism 1
• TSH: Exclude thyroid disease as cause of menstrual irregularity 2, 1
• Prolactin: Rule out hyperprolactinemia 2, 1
• 17-hydroxyprogesterone: Exclude nonclassic congenital adrenal hyperplasia 1

Metabolic Screening (Required for All PCOS Patients)

These tests assess cardiovascular and diabetes risk regardless of BMI:

• 2-hour oral glucose tolerance test with 75-gram glucose load: Screen for type 2 diabetes and glucose intolerance in all women with PCOS 2, 1
• Fasting lipid profile: Total cholesterol, LDL, HDL, and triglycerides to assess dyslipidemia driven by insulin resistance 2, 1

Additional Testing When Indicated

Consider based on clinical suspicion:

• 24-hour urinary free cortisol or dexamethasone suppression test: When Cushing's syndrome features are present 2

Imaging Assessment

Transvaginal Ultrasound (First-Line)

Use high-frequency transducer (≥8 MHz) to document:

• Follicle count: ≥25 follicles measuring 2-9 mm in diameter in at least one ovary confirms polycystic ovarian morphology 2, 1
• Ovarian volume: >10 mL suggests PCOS 2
• Stromal echogenicity: Increased echogenicity is the most sensitive and specific ultrasound sign, though subjective 2

Alternative Imaging

• Transabdominal ultrasound: Reliable for ovarian volume >10 mL but inadequate for accurate follicle counts due to lower transducer frequency 2
• MRI pelvis: Consider in obese adolescents or when transvaginal ultrasound is unacceptable; provides reproducible ovarian volume assessment 2

Diagnostic Algorithm

Step 1: Confirm at least two Rotterdam criteria are present:

1. Clinical or biochemical hyperandrogenism
2. Ovulatory dysfunction (oligomenorrhea or amenorrhea)
3. Polycystic ovarian morphology on ultrasound 1, 3

Step 2: Exclude alternative diagnoses through targeted testing:

• Thyroid disease (TSH) 1
• Hyperprolactinemia (prolactin) 1
• Nonclassic congenital adrenal hyperplasia (17-hydroxyprogesterone) 1
• Cushing's syndrome (if clinical features present) 2
• Androgen-secreting tumors (if severe/rapid-onset virilization) 2

Step 3: Assess metabolic complications in all diagnosed patients:

• Glucose tolerance testing 1
• Lipid profile 1
• Blood pressure and BMI 2

Critical Pitfalls to Avoid

• Adolescents: PCOS diagnosis is problematic in this age group; hyperandrogenism must be central to the presentation as irregular cycles are physiologic 3
• Postmenopausal women: No consistent PCOS phenotype exists; diagnosis is unreliable 3
• Acanthosis nigricans: When present, consider associated insulinoma or gastric adenocarcinoma, not just insulin resistance 2
• Normal weight patients: Do not skip metabolic screening—up to 50% of PCOS patients are normal weight but still have metabolic dysfunction 1, 4
• Incidental polycystic ovaries on ultrasound: Polycystic ovarian morphology alone without clinical/biochemical features does not establish PCOS diagnosis 5

Documentation Requirements

When confirming PCOS diagnosis, clearly document:

• Specific phenotype: Which two or three Rotterdam criteria are met 6
• Excluded diagnoses: List alternative causes ruled out 1
• Metabolic risk profile: Baseline glucose tolerance and lipid status 1
• Long-term surveillance plan: Endometrial cancer risk monitoring (obesity, chronic anovulation, hyperinsulinemia) 2, 1