Testosterone Test

About this test

This test measures the total amount of testosterone in your blood — a hormone that plays essential roles in sexual function, fertility, muscle mass, bone density, red blood cell production, energy, and mood in people of all sexes.

Testosterone levels naturally vary by time of day (highest in the morning) and decline gradually with age in both men and women. Both low and high testosterone can cause significant symptoms. This test is often paired with other hormone tests depending on your clinical picture. Morning sample collection is strongly preferred for the most accurate result.

Components

• Total Testosterone: Measures all testosterone in the bloodstream, including testosterone bound to proteins (SHBG and albumin) and the small free fraction. In men, low total testosterone (hypogonadism) commonly causes fatigue, reduced sex drive, erectile dysfunction, loss of muscle mass, and mood changes. In women, low testosterone can contribute to low libido and fatigue; high testosterone may indicate conditions such as polycystic ovary syndrome (PCOS). If symptoms suggest a problem but total testosterone is borderline, free testosterone or SHBG testing may be recommended.

Who is this test for?

Testosterone testing is most relevant for men experiencing fatigue, reduced libido, erectile dysfunction, loss of muscle mass, increased body fat, or mood changes such as depression or irritability. It is also used for women with symptoms of hormonal imbalance, irregular periods, or signs of excess androgens such as acne and unwanted hair growth. Most endocrinology guidelines suggest testing in men over 40 who have multiple symptoms of low testosterone.