A testosterone blood test can show us how much of the sex hormone testosterone is in your body. Males usually have more testosterone than females. Overview What is a testosterone test? A testosterone test measures your levels of the hormone testosterone. Testosterone is the main sex hormone in men and people assigned male at birth (AMAB). Still, women and people assigned female at birth (AFAB) also have testosterone in their bodies. About the Test Purpose of the test The purpose of testosterone testing is to evaluate the amount of the hormone in the blood. Testosterone levels that are outside of a normal range can cause changes to health and physical appearance. Measuring testosterone can help diagnose medical conditions or monitor your response to therapy: In the UK, testosterone replacement therapy is available through the National Health Service (NHS). However, to qualify for treatment, you must have your testosterone levels checked by a qualified doctor and receive an official low testosterone diagnosis. A Testosterone Free test measures the amount of testosterone that is not bound to any protein, whereas a Testosterone Total test measures the amount of total (both bound and free) testosterone in the body. Table of Contents View All What Is Testosterone? Normal Levels Symptoms Tests Treatment Testosterone is a hormone, which is a substance in the body that acts as a chemical messenger. Hormones are made in one part of your body and then travel to other areas to help control how cells and organs work. To measure your testosterone level, you can take a simple blood test. Here we explain in-office tests and at-home testosterone test kits, and what your results may mean. Tom Werner/Getty "A morning blood test before 10 a.m. is the gold standard [for testing testosterone levels accurately]," says Dr. Welliver. That's because your T levels are highest in the morning. Circulating testosterone levels in all individuals can be an indicator of reproductive health. The Bioavailable Testosterone test by LifeLabs can help identify potential conditions impacting overall wellness. Bioavailable Testosterone is associated with a variety of conditions including: T54r.