SHBG Blood Test

An SHBG blood test measures the level of a protein called sex hormone binding globulin (SHBG) in a sample of your blood. SHBG is made mostly in your liver. It binds (attaches) to sex hormones such as testosterone and estrogen and helps control how much of these hormones are active in your body.

All of the sex hormones in your blood are either bound to proteins or unbound (free). Free sex hormones work with your tissues, helping with a variety of bodily functions including bone and muscle growth and reproductive health. Sex hormones that are bound to proteins, such as SHBG, however, cannot work with your tissues.

An SHBG test is most often done if you have signs and/or symptoms of having too much or too little testosterone. Though often considered a male sex hormone, testosterone is present in females in smaller amounts. In both sexes, it helps control your sex drive and contributes to muscle and bone growth.

In males, it is also involved in: Body hair growth.; A deepening voice during puberty.; The production of sperm.; The creation of new red blood cells.; An increase in height.;

Why this test is done

You may need this test if you have signs and/or symptoms of abnormal testosterone levels, especially if results from a total testosterone test didn't explain your symptoms.

If you're male, you may need this test if you have symptoms of low testosterone levels, including:

• Low sex drive.
• Difficulty getting an erection.
• Fatigue or loss of muscle mass.
• Fertility problems.

If you're female, you may need this test if you have symptoms of high testosterone, including:

• Too much hair growth on the face and body.
• Deepening of voice.
• Having menstrual periods that aren't regular or no periods at all.
• Acne.
• Weight gain.
• Fertility problems.

Your provider may also order an SHBG test if:

• You are undergoing hormone replacement therapy or treatment for hormone disorders.
• You have signs and/or symptoms of PCOS, such as irregular menstrual periods.
• A child shows signs of early puberty.

How to prepare

You don't need any special preparations for an SHBG test. Tell your provider about all medicines, vitamins, and supplements you take. Certain medicines that contain hormones - such as birth control pills, estrogen therapy, or anabolic steroids - can affect SHBG levels.

But don't stop taking any medicines unless your provider tells you to.

Sample type

Blood

Other names for this test

testosterone-estrogen binding globulin, TeBG