Free & Bioavailable Testosterone calculator
These calculated parameters more accurately reflect the level of bioactive testosterone than does the sole measurement of total serum testosterone.
Testosterone and dihydrotestosterone (DHT) circulate in plasma unbound (free approximately 2 - 3%) ,bound to specific plasma
proteins (sex hormone-binding globulin SHBG) and weakly bound to nonspecific proteins such as albumin.
The SHBG-bound fraction is biologically inactive because of the high binding affinity of SHBG for testosterone.
Free testosterone measures the free fraction, bioavailable testosterone includes free plus weakly bound to albumin.
Disclaimer: Results from this calculator should NOT be solely relied upon in making (or refraining from
making) any decision in any case/ circumstances without the prior consultation of experts or professional
No responsability whatsoever is assumed for its correctness or suitability for any given purpose.
WARNING! The calculated free and bioavailable testosterone are reliable in most clinical situations,
but should not be relied upon in situations with potential massive interference by steroids binding to
SHBG; e.g. in women during pregnancy, in men during treatment inducing high levels of DHT (e.g. transdermal
DHT, oral testosterone) or mesterolon
This calculator was developed at the Hormonology department, University Hospital of Ghent, Belgium.
If you have suggestions to improve this calculator, or for further questions or help contact us Dr. Tom Fiers or Prof. Dr. J.M. Kaufman