What is the normal range of testosterone levels in a female patient and how is an abnormal level treated?

Testosterone Levels in Females

Normal Reference Ranges

In reproductive-age women without clinical signs of hyperandrogenism, the normal serum testosterone level is approximately 14.1 ng/dL (mean), with an upper limit of normal at 28 ng/dL (mean + 2 standard deviations). 1

Key Measurement Considerations

• Testosterone should be measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in a laboratory certified by an accuracy-based program such as the CDC's Hormone Standardization (HoST) Program, as immunoassays often lack accuracy below 100 ng/dL 2
• Free testosterone should ideally be measured by equilibrium dialysis method when total testosterone is borderline or when sex hormone-binding globulin (SHBG) abnormalities are suspected 2
• Morning fasting samples on two separate occasions are recommended for accurate assessment 2

Critical Pitfall with Commercial Laboratory Ranges

Most commercial laboratories report upper limits of normal for testosterone at 95 ng/dL, which makes detection of hyperandrogenemia essentially impossible in women. 1 This explains why hyperandrogenism is frequently missed in clinical practice—women with clear clinical hyperandrogenism often have testosterone levels that fall within these inappropriately wide "normal" ranges 1

Abnormal Testosterone Levels and Clinical Correlation

Elevated Testosterone Patterns

• Women with menstrual dysfunction but no hirsutism or acne: mean testosterone 17.9 ng/dL (significantly elevated compared to reference population) 1
• Women with mild hirsutism: mean testosterone 38.4 ng/dL 1
• Women with moderate to severe hirsutism: mean testosterone 49.0 ng/dL 1

Diagnostic Threshold

Using 28 ng/dL as the upper limit provides 84% sensitivity for detecting hyperandrogenemia in women with clinical signs of androgen excess 1

Treatment Approach for Elevated Testosterone

Step 1: Identify the Underlying Cause

Measure luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels to distinguish between ovarian and adrenal sources of androgen excess 3

• Elevated LH with normal or low FSH suggests polycystic ovary syndrome (PCOS)
• Measure DHEAS to assess adrenal contribution 1
• Consider prolactin measurement if menstrual irregularities are present 3

Step 2: Treatment Selection Based on Etiology

For PCOS-related hyperandrogenism:

• Combined oral contraceptives are first-line therapy to suppress ovarian androgen production
• Anti-androgens (spironolactone 50-200 mg daily) can be added for persistent hirsutism or acne
• Metformin may improve metabolic parameters and menstrual regularity in women with insulin resistance

For adrenal hyperandrogenism:

• Low-dose glucocorticoids may be considered if adrenal source is confirmed
• Referral to endocrinology for further evaluation of potential adrenal pathology

Step 3: Monitoring Treatment Response

• Recheck testosterone levels 3-6 months after initiating therapy
• Target testosterone levels below 28 ng/dL with resolution of clinical hyperandrogenic symptoms 1
• Monitor for treatment side effects including metabolic changes, bone density (with long-term glucocorticoid use), and cardiovascular risk factors

Special Populations

Transgender Women on Hormone Therapy

In transgender women treated with spironolactone and estrogen therapy, the highest suppressing quartile achieved testosterone levels of 27 ng/dL (SD 21 ng/dL), which aligns with the female reference range 4 Patients typically require approximately 9 months to reach steady-state testosterone levels 4