What does the Bioavailable Testosterone test measure?

Why is Bioavailable Testosterone measured?

Bioavailable testosterone offers a practical middle ground between total and free testosterone, capturing the androgen that is immediately accessible to tissues. In conditions that alter SHBG — obesity, metabolic syndrome, liver disease, thyroid dysfunction — bioavailable testosterone often correlates better with clinical signs of androgen deficiency or excess than does total testosterone, and some practitioners prefer it for the assessment of equivocal cases.

Reference ranges

Standard reference

Approximately 131–682 ng/dL (4.5–23.7 nmol/L) in adult men. Laboratory- and age-specific.

Functional medicine optimal

Optimal thresholds are less well-defined for bioavailable testosterone than for total testosterone, but values in the lower quartile of the reference range accompanied by symptoms warrant clinical consideration of hypogonadism or further evaluation.

Units

ng/dL, nmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.