Bioavailable Testosterone
Testosterone that is free or loosely bound to albumin, and therefore readily usable by tissues.
| Typical reference range (male) | 110–575 ng/dL |
| Typical reference range (female) | 0.5–8.5 ng/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Bioavailable testosterone includes free testosterone plus the fraction weakly bound to albumin, which can dissociate easily. It excludes testosterone tightly bound to SHBG.
Why it matters
Like free testosterone, it helps assess androgen status when SHBG is abnormal, particularly in older men and in women with suspected androgen excess.
What a high result can mean
High values occur with testosterone use, low SHBG or androgen excess conditions such as PCOS.
What a low result can mean
Low values occur with hypogonadism or high SHBG.
What affects the result
Usually calculated from total testosterone, SHBG and albumin, or measured by ammonium sulfate precipitation. Ranges are method-specific and age-dependent.
Units and conversion
Usually reported in ng/dL.
- From nmol/L: multiply by 28.84 to get ng/dL
Also called on lab reports
Testosterone, Bioavailable, Testosterone Bioavailable, Bioavailable Testosterone, Calculated
Related tests: Sex Hormones
This page is educational and does not replace advice from a healthcare professional.