Hypogonadism is defined by both low morning testosterone levels and symptoms of low testosterone. Low testosterone is usually defined as a testosterone level below 300 ng/dL. However, the authors concluded in their cohort that up to 20% of patients who had a testosterone level of greater than 300 ng/dL were actually hypogonadal if bioavailable testosterone (BT) was calculated using sex hormone-binding globulin (SHBG). When symptomatic patients with a BT level between 156 and 210 ng/dL were included, it was observed that up to 53% of men were hypogonadal although their testosterone levels were normal and they could have benefited from testosterone therapy. It is suggested that in assessing hypogonadism in men, SHBG might have a diagnostic role and SHBG levels independently predict decreased sperm concentration and motility when compared to follicle-stimulating hormone levels.