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.
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 Other names: testosterone-estrogen binding globulin, TeBG
Why is this test ordered? 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 therapy for menopause 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
Clinical Interpretation
Your provider will usually look at your SHBG blood test results along with the results of a total testosterone test. This helps your provider estimate how much free testosterone is in your blood. If your SHBG levels are too low , it means that more of your total testosterone is likely free and available for your body to use. Low levels of SHBG may be related to: Hypothyroidism (underactive thyroid) Type 2 diabetes or insulin resistance Obesity or being very overweight Overuse of steroid medicines and/or anabolic steroids Cushing's syndrome In females, polycystic ovary syndrome (PCOS) It's also normal for SHBG levels to decrease with older age as the production of sex hormones also decreases. If your SHBG levels are too high , it likely means that less of your total testosterone is available for your tissues to use. So, your tissues may not be getting enough testosterone. High levels of SHBG may be related to: Liver disease Hyperthyroidism (overactive thyroid) Certain eating disorders Use of estrogen-containing medicines, such as hormone therapy for menopause or birth control pills, in females Decreased production of sex hormones in males Your provider may order other tests to check if your hormones are in balance with each other. If you have questions about your results, talk with your provider. Learn more about laboratory tests, reference ranges, and understanding results .
Clinical Protocol & Patient Advice
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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.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.