Quick Facts
- Sample: Blood (serum)
- Fasting: Preferred
- Turn-around time: 5-7 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Gold-standard accuracy using equilibrium dialysis and LC/MS/MS technology
- Comprehensive hormone assessment measuring both free and total testosterone
- No doctor referral required for direct access to hormone testing
- Superior precision over immunoassays for reliable results
- Confidential results delivered directly to you
- Ideal for SHBG-affected conditions like obesity and diabetes
Who Is This Test For?
Men experiencing decreased libido, fatigue, or erectile dysfunction
Individuals monitoring testosterone replacement therapy effectiveness
People investigating fertility concerns or hormone imbalances
Those with borderline testosterone levels needing precise measurement
Transgender individuals receiving gender-affirming hormone therapy
Adults evaluating symptoms of hypogonadism
How It Works – Just 3 Steps
- Order your test online with no doctor's visit required
- Visit a lab for quick blood draw (morning collection preferred)
- Receive results securely within 5-7 business days
FAQ
What's the difference between free and total testosterone? Total testosterone measures all hormone in your blood, while free testosterone (<3% of total) represents the active form that can enter cells and affect body functions.
Why is morning collection important? Testosterone levels are highest in the morning and decline throughout the day, so early collection provides the most accurate baseline measurement.
How accurate is this test compared to others? This test uses equilibrium dialysis (gold standard) and LC/MS/MS technology, providing superior accuracy over standard immunoassays used by many labs.
Do I need to fast before testing? Fasting is preferred for optimal accuracy, and you should avoid biotin supplements for 72 hours before testing.
Can medications affect my results? Yes, steroids, opioids, and hormone therapies can impact results. Inform the lab of all medications you're taking.
What if my results are abnormal? Consult with a healthcare provider for proper interpretation and potential additional testing to determine underlying causes.
More Details
What is the purpose of this test?
This comprehensive test measures both bound and unbound testosterone to diagnose hormone imbalances, evaluate hypogonadism, assess causes of infertility, and monitor hormone therapy effectiveness (Endocrine Society 2018). The test employs high-pressure liquid chromatography with tandem mass spectrometry for total testosterone and equilibrium dialysis for free testosterone, providing highly accurate results that meet CDC standardization protocols.
Who would benefit from this test?
This test is specifically recommended for women, children, and men with suspected hypogonadism, especially those with conditions affecting SHBG levels like obesity or diabetes (LabCorp 2025). It's particularly valuable for individuals experiencing symptoms of hormone imbalance, those monitoring testosterone replacement therapy, or people investigating fertility concerns without requiring an initial doctor's visit.
When should I order Testosterone Free (Dialysis) and Total Testosterone?
Consider ordering when experiencing symptoms such as decreased libido, erectile dysfunction, fatigue, muscle weakness, enlarged breasts in men, or when monitoring hormone therapy (Walk-In Lab 2025). The test is also valuable for investigating early or delayed puberty in adolescents, evaluating hormone levels in transgender individuals, and assessing unexplained infertility in both men and women.
How do I interpret the results?
Results should be evaluated against age-appropriate reference ranges and clinical symptoms together. Generally, total testosterone below 300 ng/dL may indicate hypogonadism when accompanied by symptoms.
Above 300 ng/dL
- What it means: Normal range
- Typical action: Monitor if symptomatic
200–300 ng/dL
- What it means: Borderline low
- Typical action: Consider free testosterone testing
Below 200 ng/dL
- What it means: Low testosterone
- Typical action: Evaluate for hypogonadism
Free testosterone represents the biologically active hormone fraction, crucial when SHBG levels are altered by conditions like obesity, diabetes, or aging.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
Morning collection is strongly recommended as testosterone levels exhibit significant diurnal variation and are highest in the morning. Fasting is preferred for more accurate results. Avoid biotin supplements for at least 72 hours before testing as they can interfere with hormone assays. Inform the lab of any medications you're taking, especially steroids, opioids, or hormone therapies that may affect results.
How often should I get tested?
- Baseline screening: Every 2–3 years after age 40
- Monitoring therapy: Every 3–6 months initially, then annually
- Symptomatic individuals: Retest in 2–4 weeks to confirm
- High-risk conditions (e.g., diabetes, obesity): Annually
Why early detection matters
Approximately 40% of men older than 45 have hypogonadism, yet treatment rates have decreased from 32.9% to 20.8%, indicating significant gaps in diagnosis (Nature Scientific Reports 2021). Early detection enables timely intervention to address symptoms like fatigue, decreased muscle mass, and reduced quality of life. Men with obesity have 2.38 times higher odds of hypogonadism, while those with diabetes have 2.09 times higher odds (Journal of Clinical Endocrinology & Metabolism 2006).
Related tests you may consider
Sex Hormone-Binding Globulin (SHBG) - measures the main protein that binds testosterone, helping interpret results in obesity, liver disease, or thyroid disorders.
Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) - help distinguish between primary and secondary hypogonadism, guiding treatment approaches.
Comprehensive Metabolic Panel - provides valuable context by assessing liver function, kidney function, and glucose levels that can impact testosterone production.
