Total Free Testosterone (Serum/Plasma)
This test measures the amount of free (unbound) testosterone in your blood, which is the active form of the hormone that regulates male and female sex characteristics.
["Understanding your free testosterone levels helps assess hormone balance and potential hormone-related health concerns."]
Key facts at a glance
- LOINC
- 58952-3
- Short code
- Testost free+total panel SerPl-mCnc
- Synonyms
- Testost free+total panel SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 44
- Ref high
- 147
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84075
- SNOMED
- 27550007
- 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 This Test Is Done
Your healthcare provider may order this test if you have symptoms of hormone imbalances, such as irregular menstrual cycles, low libido, or unexplained fatigue. It may also be used in fertility evaluations, monitoring conditions like polycystic ovary syndrome (PCOS), or evaluating hormone replacement therapy.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your blood is drawn in the morning, but confirm with your provider. Wear comfortable clothing and plan to sit or lie down for a short time afterward.
What the Test Involves
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but it typically doesn’t cause significant discomfort. The blood sample is then sent to a lab for analysis.
What the Results Mean
Results are interpreted based on your age, sex, and overall health. High levels may indicate conditions like Cushing’s syndrome or androgen-secreting tumors, while low levels could suggest hypogonadism or other endocrine disorders. Your provider will discuss these findings in the context of your medical history.
Reference range
Adult: 44-147 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Free testosterone level
Frequently asked questions
What does my free testosterone level tell me about my health?
How often should I get this test?
Can diet or lifestyle affect my testosterone levels?
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