Testosterone Free LIS Code: TFc
Check your calculated free testosterone levels with a private blood test. Book at our Slough, Victoria or Neasden clinics, or order an at-home kit.
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About this test
What is Calculated Free Testosterone?
Free testosterone is the portion of testosterone in the blood that is not bound to proteins and is therefore biologically active. Most testosterone circulates bound to Sex Hormone Binding Globulin (SHBG) and albumin, leaving only a small fraction "free" and available for the body to use.
Rather than measuring free testosterone directly, this test calculates it using total testosterone, SHBG, and albumin levels, applying a validated mathematical formula (commonly the Vermeulen equation). This calculated method is widely regarded as a reliable and cost-effective alternative to direct free testosterone assays.
Why Choose the Calculated Method?
Direct free testosterone tests can be less accurate, particularly at lower concentrations. The calculated method is often preferred by clinicians because it:
- Provides a more precise estimate at low testosterone levels
- Accounts for changes in SHBG, which can affect how much testosterone is "available" even when total testosterone appears normal
- Is used in many clinical guidelines for diagnosing hormone imbalances
When is This Test Recommended?
Calculated free testosterone is particularly useful when SHBG levels may be affecting the accuracy of a total testosterone reading. This can occur in conditions such as:
- Obesity or metabolic syndrome
- Thyroid disorders
- Liver disease
- Ageing (SHBG naturally rises with age in men)
- Use of certain medications, including some hormone therapies
In men, this test can help identify symptoms of low free testosterone, including:
- Reduced libido
- Erectile dysfunction
- Fatigue and low energy
- Difficulty building or maintaining muscle mass
- Low mood
In women, calculated free testosterone can help investigate symptoms linked to hormone imbalance, such as those seen in polycystic ovary syndrome (PCOS), including excess hair growth, acne, and irregular cycles.
Hormone Testing Services with VitaLync
Understanding your free testosterone levels gives a clearer picture of your hormonal health than total testosterone alone.
Book a clinic appointment at our Slough clinic: https://vitalync-diagnosis.com/locations/private-blood-test-slough/
Find our Victoria and Neasden locations: https://vitalync-diagnosis.com/our-locations
Or choose our convenient at-home testing kit — collect your sample at a time that suits you and post it back to our lab, with results delivered securely online: https://vitalync-diagnosis.com/at-home-tests/testosterone-at-home-test/
