Free Testosterone (Serum)
This test measures the amount of free (unbound) testosterone in your blood. Testosterone is a hormone important for male and female health, including muscle and bone strength, mood, and sex drive.
["Understanding your free testosterone levels can help assess hormone balance and potential health concerns."]
Key facts at a glance
- LOINC
- 17685-9
- Short code
- Testost Free Dial fld-mCnc
- Synonyms
- Testost Free Dial fld-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a free testosterone test to evaluate hormone function, diagnose conditions like low testosterone (hypogonadism), or check for hormonal imbalances that could affect fertility, energy levels, or other health issues.
What Does the Test Involve?
A blood sample is taken from a vein in your arm. The test measures the unbound (free) form of testosterone, which is the active, biologically available portion of the hormone. This is distinct from total testosterone, which includes both free and protein-bound forms.
Preparation for the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if instructed by your doctor. Avoid smoking or consuming alcohol for 24 hours before the draw.
What Are Possible Results?
Results are not provided with specific reference ranges, as they vary by lab and individual factors. Your doctor will interpret the results in the context of your overall health and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free testosterone levels can indicate whether your hormone system is functioning properly. Low levels may suggest conditions like hypogonadism, adrenal insufficiency, or other endocrine disorders. High levels could be linked to conditions like Cushing’s syndrome or androgen excess. Always discuss results with your healthcare provider.
Short name
Free testosterone level
Frequently asked questions
How long does it take to get my results?
Can I eat or drink before this test?
What if my results are outside the normal range?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy