| name | eso-pediatric-obesity-pcos-hormone-interpretation |
| description | Interprets free and total testosterone and SHBG levels to screen for hyperandrogenism in adolescents with obesity, using Endocrine Society PCOS guidelines. Trigger phrases include oligomenorrhea, hirsutism, acne, and elevated androgen symptoms prompting PCOS evaluation. |
Interpret Hormone Tests for PCOS Screening per Endocrine Society Guidelines
STEP 1 — Gather Information
Collect age, Tanner stage, menstrual history (oligomenorrhea/amenorrhea), clinical signs of hyperandrogenism (hirsutism score, acne severity), and laboratory values: total testosterone (ng/dL), SHBG (nmol/L), and albumin (g/dL) if calculating free testosterone; alternatively, directly measured free testosterone.
STEP 2 — Rule In / Rule Out
Determine if total testosterone exceeds age‑ and Tanner‑stage‑specific thresholds (e.g., >55 ng/dL in mid‑late puberty) or if calculated free testosterone >6 pg/mL (≈0.2 nmol/L). If neither is elevated, rule out PCOS‑related hyperandrogenism.
STEP 3 — Classify or Stratify
If total testosterone or free testosterone is elevated, calculate the Free Androgen Index (FAI) = (total testosterone [ng/dL] ÷ SHBG [nmol/L]) × 100. FAI > 5–7 suggests significant hyperandrogenism; otherwise consider mild or assay‑related variation.
STEP 4 — Decide
If hyperandrogenism is confirmed (elevated testosterone/FAI) and the patient has oligomenorrhea/amenorrhea or polycystic ovarian morphology on ultrasound, proceed to formal PCOS diagnosis per Rotterdam criteria; if hyperandrogenism is isolated, evaluate for other causes (e.g., congenital adrenal hyperplasia, androgen‑secreting tumor) before labeling PCOS.
Clinical Guardrails / Mimics / Pitfalls
Use LC‑MS/MS assays for testosterone; immunoassays overestimate in obesity. Low SHBG in obesity can falsely elevate calculated free testosterone—confirm with direct free testosterone or equilibrium dialysis. Do not rely on total testosterone alone in obese adolescents.
Concrete Clinical Example
A 16‑year‑old, Tanner 4, obese girl reports 45‑day cycles and mild facial hirsutism. Labs: total testosterone 48 ng/dL, SHBG 15 nmol/L, albumin 4.2 g/dL. Calculated free testosterone ≈0.32 ng/dL (11 pg/mL) and FAI = 320, both above cutoffs, indicating hyperandrogenism; further evaluation for PCOS is warranted.
Source: Pediatric Obesity Assessment, Treatment, and Prevention: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2017, doi:10.1210/jc.2016-2573
TODO: consider adding scripts/calc.py for the eso-pediatric-obesity-pcos-hormone-interpretation calculator
