| name | endo-hirsutism-measure-free-testosterone-if-indication |
| description | The clinician orders early morning serum total and free testosterone when total testosterone is normal but the patient presents with moderate to severe hirsutism or mild hirsutism accompanied by signs of hyperandrogenism such as menstrual irregularity or lack of response to therapy. This is indicated when a clinician questions whether to check free testosterone in a patient with normal total testosterone but worsening hirsutism and irregular periods. |
Measure free testosterone when total testosterone is normal but clinical signs suggest hyperandrogenism
STEP 1 — Gather Information
Document hirsutism severity (Ferriman–Gallwey score or clinical assessment of sexual hair growth), menstrual pattern, prior therapeutic response, and any existing total testosterone level.
STEP 2 — Rule In / Rule Out
Is the serum total testosterone level normal? If abnormal, evaluate for hyperandrogenism; if normal, proceed to assess hair growth severity and clinical evidence of hyperandrogenism.
STEP 3 — Classify or Stratify
If sexual hair growth is moderate/severe OR mild with clinical evidence of a hyperandrogenic disorder (e.g., menstrual disturbance, lack of response to therapy), proceed to measure free testosterone; otherwise, consider idiopathic hirsutism.
STEP 4 — Decide
Order an early morning serum total and free testosterone using a reliable specialty assay; if criteria are not met, manage as idiopathic hirsutism with cosmetic measures or oral contraceptive therapy.
Clinical Guardrails / Mimics / Pitfalls
Do not rely on total testosterone alone; ensure early morning sample when androgen levels peak; use a validated specialty assay (e.g., mass spectrometry) rather than routine immunoassays; avoid testing in eumenorrheic women with only local hair growth and no hyperandrogenic signs; be aware of SHBG variability affecting free testosterone interpretation; do not test if the patient is currently using combined oral contraceptives, which suppress androgen levels; consider pregnancy as a cause of menstrual changes; avoid repeating free testosterone testing if total and free testosterone are normal and there is no progression of hirsutism.
Concrete Clinical Example
A 28‑year‑old woman presents with mild hirsutism (Ferriman–Gallwey score 9) and worsening oligomenorrhea. Her total testosterone is normal, and she has had minimal improvement with topical therapy. According to the guideline, early morning serum total and free testosterone are ordered.
Source: Evaluation and Treatment of Hirsutism in Premenopausal Women: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2018, doi:10.1210/jc.2018-00241
