The Bioavailable Testosterone test measures the fraction of testosterone that is not tightly bound to proteins like sex hormone-binding globulin (SHBG) and is therefore available for biological activity. This includes free testosterone and albumin-bound testosterone.
Unlike total testosterone, bioavailable testosterone provides a more accurate assessment of the hormone that is actively accessible to tissues. It is particularly useful in evaluating cases where total testosterone levels appear normal but symptoms of deficiency or excess are present.
The purpose of this test is to