An SHBG Blood Test measures the level of sex hormone binding globulin (SHBG) in your blood. SHBG is a protein that binds to three sex hormones found in both men and women: testosterone, dihydrotestosterone, and estradiol.
An SHBG blood test measures the amount of free testosterone in your bloodstream. It is primarily used to help evaluate men for low testosterone and women for excess testosterone. Normal SHBG levels vary according to gender, age and medical history. However, many other factors can influence SHBG levels and cause them to be abnormally low or high.