What does the Total Testosterone test measure?

Why is Total Testosterone measured?

Total testosterone is the first-line biochemical marker for male hypogonadism and is used to investigate low libido, erectile dysfunction, fatigue, reduced muscle mass, and infertility. Because the majority is protein-bound, total testosterone can be misleading when SHBG is abnormal — obesity and metabolic syndrome lower SHBG and total testosterone, while ageing and hyperthyroidism raise SHBG, potentially masking low free hormone. For this reason total testosterone is most informative when measured alongside free testosterone or calculated free testosterone.

Reference ranges

Standard reference

Approximately 264–916 ng/dL (9.2–31.8 nmol/L) in adult men; 15–70 ng/dL (0.5–2.4 nmol/L) in adult women. Age- and sex-specific; consult laboratory intervals.

Functional medicine optimal

For hypogonadism diagnosis, most endocrinology societies use a lower threshold of 300 ng/dL (10.4 nmol/L) as a pragmatic cut-point, though symptom correlation and repeat testing are essential; some functional-medicine sources suggest higher targets for well-being, but these lack consensus validation.

Units

ng/dL, nmol/L

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