Serum/plasma free testosterone concentration (mass concentration)
This test measures the amount of free (unbound) testosterone in your blood, which is an important hormone for men and women. Free testosterone is the biologically active form that directly affects sex drive, muscle mass, and overall health.
["Understanding your free testosterone levels can help assess hormone balance and potential health risks."]
Key facts at a glance
- LOINC
- 27851-5
- Short code
- LH sp3 p chal SerPl-aCnc
- Synonyms
- LH sp3 p chal SerPl-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 1.5
- Ref high
- 9
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 83002
- 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 healthcare provider may order a free testosterone test to evaluate symptoms related to hormone imbalances, such as low libido, fatigue, or changes in body hair. It’s also used in fertility evaluations, hormone replacement therapy planning, or monitoring conditions like polycystic ovary syndrome (PCOS) or hypogonadism.
What to Expect Before the Test
No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before drawing blood, but this depends on your provider’s instructions. Avoid smoking or consuming alcohol for at least 24 hours before testing.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. The blood will be sent to a lab for analysis. The test typically takes a few minutes, and you can resume normal activities afterward.
What Are the Results?
Results are reported as a mass concentration (measured in picograms per milliliter, pg/mL). Your provider will compare these results to your individual reference range and clinical context to interpret them.
Reference range
Follicular: 1.5-9.0 mIU/mLN/A
For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free testosterone levels can help diagnose or monitor conditions affecting hormone function. Low free testosterone may indicate hypogonadism, while high levels could suggest conditions like Cushing’s syndrome or androgen excess. It’s particularly useful in diagnosing fertility issues or evaluating symptoms of hormone-related disorders.
Short name
Free Testosterone
Frequently asked questions
What Does a Low Free Testosterone Level Mean?
What Does a High Free Testosterone Level Mean?
How Often Should I Get This Test?
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