Multiple problems can be diagnosed in men, women, girls, and boys with testosterone testing. Male physical traits are a result of testosterone, which is the primary sex hormone in males and is mostly generated by the testicles. Although it is thought to be a masculine sex hormone, both males and females have it in their blood. The blood contains approximately two thirds of testosterone bound to sex hormone-binding globulin (SHBG) and just under one third attached to albumin. Less than 4% of testosterone circulates in the body as free testosterone. The bioavailable testosterone, which can affect target tissues, is made up of free testosterone and testosterone bound to albumin. The total testosterone test frequently gives accurate results. However, in certain cases, for example when the level of SHBG is abnormal, a test for free or bioavailable testosterone may be performed as it may more accurately reflect the presence of a medical condition.