Some of the terminology for testosterone can be confusing. Here is a simple way to understand the different measurements. There are 3 types of testosterone:
- The majority of Bioavailable Testosterone is testosterone that is loosely bound to a protein called albumin. The rest of the bioavailable testosterone is free testosterone which not bound to any protein or carrier. Bioavailable Testosterone is not bound to Sex Hormone Binding Globulin (SHBG).
- Free Testosterone only accounts for .5-3% of total testosterone and is not combined with SHBG or albumin.
Total Testosterone is all the testosterone in the sample, free testosterone, testosterone bound to albumin and testosterone bound to SHBG.