🔬 PCOS Diagnostic Guide

Polycystic ovary syndrome — 2023 International Evidence-based Guideline

Purpose
Structured diagnostic algorithm for PCOS with phenotype classification, based on the 2023 International Evidence-based Guideline (Teede et al.).
Population
Women of reproductive age (any age post-menarche). Adapted criteria for adolescents (<8 years post-menarche). Dermatology-focused: hyperandrogenic acne, hirsutism, and FPHL.
Criteria (2023)
≥ 2 of 3: (1) Clinical/biochemical hyperandrogenism · (2) Ovulatory dysfunction · (3) PCOM on ultrasound or elevated AMH + Exclusion of other causes
2023 update
AMH can now replace ultrasound to define PCOM in adults. If both irregular cycles AND hyperandrogenism are present, ultrasound/AMH are NOT required.
📋 Diagnostic Workup Checklist

Quick reference for complete diagnostic assessment.

🩺 Clinical
Menstrual history (cycle length, regularity, duration)
Hirsutism — Ferriman-Gallwey score
Acne — severity, distribution, morphology
Female pattern hair loss
BMI · waist circumference · blood pressure
Acanthosis nigricans
Signs of virilisation
Psychological screening (depression, anxiety)
🧪 Biochemical
Fasting · day 2–5 · off COCP ≥ 3 months
TSH
Prolactin
17-hydroxyprogesterone
Total testosterone + SHBG
Androstenedione + DHEAS
75g oral glucose tolerance test
Fasting lipid profile
Anti-Müllerian hormone
Cortisol (if Cushing suspected)
🔬 Pelvic Imaging
Pelvic ultrasound — transvaginal (day 2–5)
Follicle count per ovary (≥ 20 follicles, 2–9 mm)
Ovarian volume per ovary (≥ 10 mL)
Exclude dominant follicles / cysts
⚠️ Not recommended in adolescents
🚫 Step 1 — Exclude Other Aetiologies

Before diagnosing PCOS, the following conditions must be excluded. Order appropriate tests based on clinical suspicion.

  • TSH Thyroid dysfunction — hypothyroidism and hyperthyroidism can cause menstrual irregularities and overlap with PCOS features.
  • Prolactin Hyperprolactinaemia — elevated PRL causes oligo/amenorrhoea and can be confused with PCOS-related ovulatory dysfunction.
  • 17-OHP Non-classic congenital adrenal hyperplasia (21-OHD) — measure basal follicular-phase 17-hydroxyprogesterone. Stimulated test if >2 ng/mL (>6 nmol/L).
  • Clinical Cushing's syndrome — consider if rapid weight gain, central adiposity, striae, proximal myopathy, or severe hypertension. Order 24h urinary free cortisol or 1mg dexamethasone suppression test.
  • T, DHEAS Androgen-secreting tumour / ovarian hyperthecosis — suspect if rapid onset of virilisation, markedly elevated testosterone (>5 nmol/L or >1.5 ng/mL) or DHEAS. Pelvic ultrasound and referral if suspected.
🧭 Step 2 — Assess Diagnostic Criteria

Patient age group

💡 2023 Guideline shortcut: If criteria 1 (hyperandrogenism) AND 2 (ovulatory dysfunction) are both present, PCOS diagnosis is confirmed — criterion 3 (PCOM/AMH) is NOT required.
🔤 Abbreviations used in this section ▸
HA = hyperandrogenism · mFG = modified Ferriman-Gallwey (hirsutism scale) · FPHL = female pattern hair loss · T = testosterone · FAI = free androgen index (T / SHBG × 100) · SHBG = sex hormone-binding globulin · DHEAS = dehydroepiandrosterone sulphate · LC-MS/MS = liquid chromatography tandem mass spectrometry · COCP = combined oral contraceptive pill · OD = ovulatory dysfunction · PCOM = polycystic ovarian morphology · AMH = anti-Müllerian hormone (must be elevated) · FNPO = follicle number per ovary · OV = ovarian volume · FNPS = follicles per cross-section
🧪
Criterion 1
Not met
Clinical / Biochemical Hyperandrogenism
Clinical HA — any of:
Biochemical HA — any of:
ℹ️ Clinical OR biochemical HA is sufficient — both are not required.
LC-MS/MS preferred. COCP suppresses androgens — withdraw ≥ 3 months before testing. Approximate cut-offs (assay-specific): Total T > 2.5 nmol/L (> 72 ng/dL) · Free T or FAI: lab upper limit · Androstenedione > 3.5 nmol/L · DHEAS > 7.9 μmol/L. Always use your lab's reference range.
⚠️ Acne or hair loss alone are weak predictors of hyperandrogenism per the 2023 guideline. Biochemical confirmation is strongly recommended.
📅
Criterion 2
Not met
Ovulatory Dysfunction
Irregular cycles — any of:
Anovulation can occur with regular cycles — confirm with mid-luteal progesterone if needed.
🔬
Criterion 3
Not met
PCOM (Ultrasound or AMH)
Ultrasound (transvaginal) — any of:
OR AMH (adults only — elevated):
⬆️ AMH must be elevated above the assay/population-specific cut-off. Low AMH does not fulfil this criterion.
US or AMH — not both (over-diagnosis risk). Not recommended in adolescents.
0 criteria met
Select the sub-criteria present in the patient above.
📊 PCOS Phenotypes — Classification

The 2003 Rotterdam criteria define four phenotypes based on which diagnostic criteria are present. Phenotypes A and B carry the highest metabolic risk. Phenotype D is not recognized by the AE-PCOS Society (2006).

Phenotype HA OD PCOM Severity Clinical notes
A ✓ ✓ ✓ Severe Classic phenotype. Highest prevalence of metabolic syndrome, insulin resistance, and dyslipidaemia. Greatest hyperandrogenic features.
B ✓ ✓ — Severe Classic phenotype. Similar metabolic risk to A. Pronounced menstrual dysfunction and androgen excess.
C ✓ — ✓ Moderate Ovulatory PCOS. Intermediate metabolic risk. Regular cycles but androgen-driven skin findings (acne, hirsutism).
D — ✓ ✓ Mild Non-hyperandrogenic PCOS. Least metabolic dysfunction. Not recognized by AES 2006. Most common in unselected (non-clinic) populations.

HA = hyperandrogenism · OD = ovulatory dysfunction · PCOM = polycystic ovarian morphology · AMH = anti-Müllerian hormone · mFG = modified Ferriman-Gallwey · FPHL = female pattern hair loss · COCP = combined oral contraceptive pill · FAI = free androgen index · SHBG = sex hormone-binding globulin · FNPO = follicle number per ovary · OV = ovarian volume · FNPS = follicle number per cross-section · DHEAS = dehydroepiandrosterone sulphate · 17-OHP = 17-hydroxyprogesterone · OGTT = oral glucose tolerance test · AES = Androgen Excess Society

🩺 Dermatological Features & Assessment
Hirsutism
Use modified Ferriman-Gallwey scale (mFG). Threshold: ≥ 4–6 depending on ethnicity (lower for East Asian, higher for Mediterranean/South Asian). Score terminal hair in 9 areas: upper lip, chin, chest, upper abdomen, lower abdomen, upper arm, thigh, upper back, lower back. Women commonly self-treat — clinical severity may be underestimated.
Androgenic Acne
Acne alone is a weak predictor of PCOS. Acne + irregular cycles → assess for PCOS. Acne + hirsutism → strong indication for biochemical androgen workup. Acne + FPHL + irregular cycles → high suspicion. No universally validated acne scale for PCOS assessment — describe distribution, morphology and severity.
Female Pattern Hair Loss (FPHL)
Assess with Ludwig or Olsen visual scales. FPHL alone is a weak predictor of biochemical HA in PCOS. Consider PCOS workup if FPHL occurs alongside other androgen excess signs or irregular cycles. Rapid worsening: rule out androgen-secreting tumour.
Red Flags — Refer / Investigate
Rapid onset or rapidly worsening hyperandrogenism, virilisation, clitoromegaly, voice deepening, testosterone > 5 nmol/L (>1.5 ng/mL) → androgen-secreting tumour / ovarian hyperthecosis. Urgent referral and imaging required.
🧾 Recommended Diagnostic Workup
Androgen Assessment
Total testosterone + free testosterone (or FAI). If normal: add androstenedione + DHEAS. Use LC-MS/MS — immunoassays inaccurate. Draw fasting, follicular phase (days 2–5). Off COCP ≥ 3 months if possible.
Exclusion Tests
TSH · Prolactin · 17-OHP basal (follicular). Add cortisol (if Cushing suspected). DHEAS markedly elevated → adrenal tumour.
Pelvic Ultrasound
Transvaginal (preferred). FNPO ≥ 20 in ≥1 ovary, or OV ≥ 10 mL. Performed in follicular phase, avoiding mid-cycle. Not recommended in adolescents.
Metabolic Assessment (at diagnosis)
75g OGTT (preferred over fasting glucose + HbA1c for accuracy). Fasting lipid profile. Blood pressure. Reassess OGTT every 1–3 years. Consider BMI + waist circumference.
Psychological Screening
Screen all patients for depression and anxiety at diagnosis using validated regional tools. Repeat at clinical judgement. Also screen for eating disorders and assess quality of life and body image.
AMH (alternative to ultrasound)
Can replace ultrasound to define PCOM in adults. Use assay/population-specific cutoffs. Not recommended in adolescents. Do not perform BOTH AMH and ultrasound (over-diagnosis risk).
💊 Treatment Overview — Dermatology-Relevant

Treatment should be symptom-oriented and individualized. Refer to endocrinology/gynaecology for metabolic/fertility management.

COCP — First Line
For hirsutism + irregular cycles. Low-dose EE (<30 μg) preferred. No specific COCP type recommended. 35 μg EE + cyproterone acetate: second-line COCP (balance VTE risk). Minimum 6 months before assessing hair response.
Anti-Androgens (+ effective contraception)
After ≥6 months COCP without adequate response. Spironolactone 25–100 mg/day: preferred (lower adverse effect risk). CPA ≥10 mg: risk of meningioma — avoid. Finasteride: hepatotoxicity risk. Flutamide/bicalutamide: severe hepatotoxicity — avoid. Mandatory: effective contraception (risk of male foetal undervirilisation).
Laser / Light Therapy
Evidence-based for facial hirsutism. Reduces hair density, depression, anxiety and improves quality of life. Best results with concurrent COCP ± anti-androgens. Multiple sessions required.
Lifestyle — For All
Healthy diet + regular exercise improve metabolic health, hormonal profiles and menstrual regularity regardless of weight. Focus on prevention of excess weight gain. No single diet type recommended over another.
👥 Special Populations
Adolescents
BOTH hyperandrogenism AND ovulatory dysfunction required. Year 1 post-menarche: do not diagnose. Irregular cycles normal up to 2 years post-menarche. PCOM/AMH: NOT recommended (poor specificity). If only 1 criterion: "increased risk" — reassess at/before 8 years post-menarche. Elevated androgens only need to persist >1–2 years post-menarche.
Perimenopause / Postmenopause
PCOS diagnosis is lifelong. Post-menopausal diagnosis: based on history of menstrual dysfunction + HA during reproductive years (age 20–40). PCOM less useful post-menopause (age-related ovarian changes). New-onset/worsening HA after menopause: rule out androgen-secreting tumour and ovarian hyperthecosis.
📚 References
  1. Teede HJ, Tay CT, Laven JJE, et al.; on behalf of the International PCOS Network. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab. 2023;108(10):2447–2469. doi:10.1210/clinem/dgad463
  2. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group. Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Fertil Steril. 2004;81(1):19–25.
  3. Azziz R, Carmina E, Dewailly D, et al.; Androgen Excess Society. Positions statement: criteria for defining polycystic ovary syndrome as a predominantly hyperandrogenic syndrome. J Clin Endocrinol Metab. 2006;91(11):4237–45.
  4. Lizneva D, Suturina L, Walker W, Brakta S, Gavrilova-Jordan L, Azziz R. Criteria, prevalence, and phenotypes of polycystic ovary syndrome. Fertil Steril. 2016;106(1):6–15.
  5. Escobar-Morreale HF. Polycystic ovary syndrome: definition, aetiology, diagnosis and treatment. Nat Rev Endocrinol. 2018;14(5):270–284.
  6. Legro RS, Arslanian SA, Ehrmann DA, et al.; Endocrine Society. Diagnosis and treatment of polycystic ovary syndrome: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2013;98(12):4565–92.
Clinical decision support only. This tool is intended to assist clinical assessment and does not replace professional judgment. Always interpret results in the context of the individual patient.