SHBG Blood Test
Reviewed
Also called: Testosterone-Estrogen Binding Globulin, TeBG
An SHBG blood test measures the level of a protein called sex hormone binding globulin (SHBG) in a sample of your blood.
Specimen: blood
Why this test may be ordered
- You have symptoms of low testosterone (e.g., low sex drive, difficulty getting an erection, fatigue, loss of muscle mass, fertility problems) and a total testosterone test did not explain them.
- You have symptoms of high testosterone (e.g., too much hair growth on face/body, deepening voice, irregular or absent periods, acne, weight gain, fertility problems) and a total testosterone test did not explain them.
- Your provider suspects a hormonal disorder such as polycystic ovary syndrome (PCOS).
- You are undergoing hormone replacement therapy or treatment for hormone disorders.
- A child shows signs of early puberty.
Preparation and collection
You don't need any special preparations for an SHBG test. Tell your provider about all medicines, vitamins, and supplements you take. But don't stop taking any medicines unless your provider tells you to.
A health care professional will take a blood sample from a vein in your arm, using a small needle. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
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.
- Low SHBG level: 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). Limitation: It's also normal for SHBG levels to decrease with older age as the production of sex hormones also decreases. Next step: Your provider may order other tests to check if your hormones are in balance with each other.
- High SHBG level: If your SHBG levels are too high, it likely means that less of your total testosterone is available for your tissues to use. 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. Limitation: Certain medicines that contain hormones - such as birth control pills, estrogen therapy, or anabolic steroids - can affect SHBG levels. Next step: If you have questions about your results, talk with your provider.
- An SHBG test alone cannot diagnose polycystic ovary syndrome (PCOS); it can help providers make a diagnosis when paired with other test results.
- Your provider will usually interpret SHBG results together with a total testosterone test to estimate free testosterone levels.
- Certain medicines containing hormones (such as birth control pills, estrogen therapy, or anabolic steroids) can affect SHBG levels.
What to do next
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.
- What do my SHBG and total testosterone results together suggest about my free testosterone level?
- Do I need any additional tests to understand my hormone balance?
- How do my current medicines or supplements affect my SHBG level?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.