Testosterone, Free (Dialysis) and Total, MS

This test measures the amount of testosterone in your blood in two ways: the total amount and the 'free' amount that is actually available for your body to use. Testosterone is an important hormone for both men and women, affecting energy, muscle mass, bone strength, mood, and sexual health. The test uses a highly accurate laboratory method called mass spectrometry, along with a special technique to measure the active portion of testosterone. Your doctor uses these results—along with your symptoms and other tests—to evaluate whether your hormone levels are in a healthy range for your age and sex. Abnormal results can have many causes and always require further evaluation by a healthcare provider.

When elevated: Elevated total and/or free testosterone may indicate androgen excess states such as polycystic ovary syndrome (PCOS) in women, androgen-secreting tumors of the adrenal glands or gonads, congenital adrenal hyperplasia, or exogenous androgen use. In men, supraphysiologic levels are most commonly associated with exogenous testosterone or anabolic steroid administration. High free testosterone with normal total testosterone may reflect decreased SHBG, amplifying androgenic effects. When low: Low total and/or free testosterone may be associated with hypogonadism (primary or secondary), hypopituitarism, Klinefelter syndrome, chronic illness, obesity, opioid use, glucocorticoid excess, or aging-related androgen decline. In women, low testosterone may contribute to reduced libido, fatigue, and decreased bone density, though clinical thresholds are less well-established. Low free testosterone with normal total testosterone may indicate elevated SHBG, effectively reducing bioavailable androgen.

Free testosterone is the biologically active fraction most directly linked to muscle protein synthesis, strength gains, and recovery from training stress. Athletes often track this marker to assess whether training load, sleep, nutrition, and stress are supporting optimal hormonal recovery—particularly important during intense phases or when plateauing in performance or body composition.