Hormone Testing for Women with Facial Hirsutism
Check total testosterone and free testosterone levels first, measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the morning, as these are the most accurate first-line tests for diagnosing hyperandrogenism in women with facial hair growth. 1
Primary Hormone Tests
- Total testosterone (TT) should be measured using LC-MS/MS methodology, which has 74% sensitivity and 86% specificity for detecting hyperandrogenism 1
- Free testosterone (FT) should be measured by equilibrium dialysis or calculated using the free androgen index (FAI = total testosterone/SHBG ratio), with 89% sensitivity and 83% specificity 1
- Morning measurement is essential due to diurnal variation in testosterone levels 1
Additional Essential Tests
- Thyroid-stimulating hormone (TSH) should be checked to rule out thyroid disease, which can present with similar symptoms 2
- Prolactin level must be measured to exclude hyperprolactinemia, which can cause hirsutism and menstrual irregularity 2, 3
Second-Line Testing (If Initial Tests Normal)
If total and free testosterone are not elevated but clinical suspicion remains high:
- Dehydroepiandrosterone sulfate (DHEAS) indicates adrenal androgen production (75% sensitivity, 67% specificity) 1
- Androstenedione (A4) can be measured (75% sensitivity, 71% specificity) 1
- 17-hydroxyprogesterone should be obtained in early morning if congenital adrenal hyperplasia is suspected 4
Critical Thresholds
- Testosterone >150 ng/dL (5.2 nmol/L) should prompt investigation for androgen-secreting tumors 5
- Very high testosterone or DHEAS levels with rapid-onset virilization suggest malignancy rather than polycystic ovary syndrome 1
Common Pitfalls
- Avoid direct immunoassay methods for free testosterone due to poor accuracy at low concentrations 1
- SHBG fluctuations from age, weight, and oral contraceptives can affect total testosterone and FAI results 1
- Do not measure androgens in women with normal menses and normal hair growth patterns 4
The most common cause of facial hirsutism is polycystic ovary syndrome (PCOS), accounting for 95% of hyperandrogenism cases 1, but testosterone measurement helps exclude more serious conditions like androgen-secreting tumors, Cushing's syndrome, and congenital adrenal hyperplasia 2.