Total Testosterone with Free and Bioavailable Subfractions (Serum/Plasma)
This test measures your total testosterone level along with the amounts of free testosterone and bioavailable testosterone in your blood. These measurements help assess hormone balance, especially important for menopause, fertility, and hormone-related conditions.
["Understanding your testosterone levels can help identify hormonal imbalances affecting energy, mood, and reproductive health."]
Key facts at a glance
- LOINC
- 40326-1
- Short code
- Testost 3h p Triple Bolus SerPl-sCnc
- Synonyms
- Testost 3h p Triple Bolus SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 80
- Ref high
- 200
- Critical range
- 20 N/A – 400 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- 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 like low energy, fatigue, changes in libido, irregular periods (in women), or unexplained infertility. It may also be used to monitor conditions such as hypogonadism, Cushing’s syndrome, or polycystic ovary syndrome (PCOS).
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your lab requires it. Wear comfortable clothing for easy access to your vein.
What the Test Results Mean
Results provide three key values: total testosterone, free testosterone, and bioavailable testosterone. These values help determine if your hormone levels are within a healthy range for your gender and age.
Common Conditions This Test Helps Diagnose
Low testosterone levels (hypogonadism) can cause symptoms like reduced muscle mass, mood swings, or difficulty concentrating. High testosterone levels may be linked to conditions like Cushing’s syndrome or androgen excess.
Reference range
Adult: 80-200 ng/dLN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Testosterone plays a critical role in muscle strength, bone density, and cognitive function. Free and bioavailable testosterone are more biologically active than total testosterone, so these measurements help pinpoint whether hormonal imbalances are due to overall low levels or specific fractions of testosterone being affected.
Short name
Testosterone profile
Frequently asked questions
What does a low testosterone result mean?
How often should I get this test?
Can lifestyle changes affect these test results?
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 17, 2026. · Read our editorial policy