Quick Facts
- Sample: Blood
- Fasting: No special preparation is required
- Turnaround: 2-4 days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures both free testosterone and total testosterone in the blood, along with the calculated percentage of free testosterone. Free testosterone is measured using equilibrium ultrafiltration, a laboratory method used to separate testosterone that is not bound to proteins. Total testosterone, which includes both bound and unbound testosterone, is measured using mass spectrometry (MS).
The % Free Testosterone value is calculated from the free and total testosterone results and reflects the proportion of testosterone that is unbound and available for use by the body. Free and total testosterone are reported as distinct, separately measured values rather than interchangeable figures.
Benefits
- Measures both free and total testosterone from a single blood draw
- Uses equilibrium ultrafiltration for free testosterone measurement
- Uses mass spectrometry for total testosterone measurement
- Reports calculated % free testosterone alongside free and total values
- Supports monitoring of testosterone replacement therapy
- No special preparation required before testing
Who Is This Test For?
- Men experiencing decreased sex drive, fatigue, or muscle weakness
- Women with symptoms such as acne, facial hair growth, or irregular periods
- Individuals undergoing hormone therapy after gender reassignment surgery
- Athletes or bodybuilders monitoring testosterone levels
- Individuals with conditions such as hypogonadism, PCOS, or pituitary gland disorders
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this hormone test?
This test measures free testosterone using equilibrium ultrafiltration and total testosterone using mass spectrometry, along with the calculated % free testosterone. These results may help a healthcare provider evaluate testosterone status as part of a broader clinical assessment. This test does not diagnose a condition on its own.
2. Who would benefit from this test?
This test may be appropriate for men experiencing symptoms associated with low testosterone, women with symptoms of elevated testosterone, individuals on hormone therapy, and athletes monitoring testosterone levels. It may also be relevant for individuals with conditions affecting testosterone, such as hypogonadism, PCOS, or pituitary gland disorders. A healthcare provider can help determine if this test is appropriate.
3. When should I order this test?
You may consider this test if you are experiencing symptoms such as reduced sex drive, erectile dysfunction, decreased muscle mass, fatigue, or irregular periods. It may also be used to monitor testosterone replacement therapy. This test does not replace a full medical evaluation, and a healthcare provider can help determine whether testing is appropriate for your situation.
4. How does this test differ from other hormone tests?
This test reports both free testosterone (directly measured by equilibrium ultrafiltration) and total testosterone (directly measured by mass spectrometry), along with a calculated % free testosterone value. Free testosterone reflects unbound, biologically available hormone, while total testosterone includes both bound and unbound testosterone. These are distinct measurements and are not interchangeable with one another.
5. Do I need to fast before this test?
No special preparation is required for this test.
6. How quickly will I get results?
Results are typically available in 2-4 days. Results may take longer based on weather, holidays, or lab delays.
7. How do I interpret the results?
Interpreting free testosterone, total testosterone, and % free testosterone depends on factors such as your symptoms, medical history, sex, age, medications, and the laboratory methodology used. These results are often considered alongside other clinical information rather than in isolation. An abnormal result does not automatically confirm a hormonal condition, and a normal result does not automatically rule one out. Free and total testosterone should be viewed as separate, non-interchangeable measurements.
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.
8. What should I do if my results are abnormal?
If your results fall outside the expected range, review them with a qualified healthcare provider. Additional evaluation or testing may be considered based on your provider's recommendation. This test result alone does not provide a complete clinical conclusion.
9. How often should I get tested?
Testing frequency should be determined as directed by your healthcare provider based on your individual health needs and the purpose of testing.
Pre test preparation
No special preparation is required.
