From the Guidelines
To evaluate elevated testosterone levels, the most direct and recommended laboratory tests are total testosterone (TT) and free testosterone (FT), which should be measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS) for high accuracy. These tests are typically drawn in the morning when testosterone levels are naturally highest, usually between 7-10 AM 1. Additional important tests include sex hormone-binding globulin (SHBG), which binds to testosterone and affects its availability, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to assess pituitary function, and sometimes dehydroepiandrosterone sulfate (DHEAS) and androstenedione to evaluate adrenal androgen production.
Key Laboratory Tests
- Total testosterone (TT)
- Free testosterone (FT)
- Sex hormone-binding globulin (SHBG)
- Luteinizing hormone (LH)
- Follicle-stimulating hormone (FSH)
- Dehydroepiandrosterone sulfate (DHEAS)
- Androstenedione In women specifically, testing should include 17-hydroxyprogesterone to rule out congenital adrenal hyperplasia. If polycystic ovary syndrome is suspected, pelvic ultrasound may be recommended 1. These comprehensive tests help determine whether elevated testosterone is due to primary gonadal issues, pituitary dysfunction, adrenal disorders, or exogenous testosterone use. Multiple measurements are often necessary as testosterone levels can fluctuate throughout the day and in response to various factors including stress, exercise, and certain medications.
Considerations for Testing
- Test timing: Morning, between 7-10 AM
- Test methodology: LC-MS/MS for high accuracy
- Additional tests: Depending on patient symptoms and suspected underlying conditions It's essential to follow the most recent guidelines, such as those informed by the 2023 International PCOS Evidence-based Guidelines, which recommend using TT and FT as the first-line laboratory tests to assess biochemical hyperandrogenism in the diagnosis of PCOS 1.
From the Research
Labs for Elevated Testosterone
To diagnose elevated testosterone levels, several lab tests can be used, including:
- Total testosterone levels
- Free testosterone levels
- Luteinizing hormone (LH) levels
- Follicle-stimulating hormone (FSH) levels
- Sex hormone-binding globulin (SHBG) levels
- Estradiol levels
Measurement of Testosterone Levels
Testosterone levels can be measured using various methods, including:
- Radioimmunoassay (RIA)
- Enzyme-linked immunosorbent assay (ELISA)
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) According to 2, total testosterone, estradiol, SHBG, LH, and FSH levels were significantly greater in men with Graves' disease compared to age-matched controls.
Role of LH and FSH in Testosterone Production
LH and FSH play a crucial role in regulating testosterone production, as stated in 3 and 4. LH stimulates the production of testosterone, while FSH regulates the proliferation and maturation of germ cells.
Factors Affecting Testosterone Levels
Several factors can affect testosterone levels, including:
- Altitude: High altitude can suppress LH, FSH, and testosterone levels, as reported in 5
- Hypothyroidism: Hyperthyroidism can lead to abnormalities in the hypothalamic-pituitary-testicular axis, resulting in changes in testosterone levels, as seen in 2
- Testosterone therapy: Monitoring of testosterone levels is essential during testosterone therapy to ensure adequate treatment, as recommended in 6