Sex Hormone Binding Globulin Test (SHBG)-Why am I having this test?

Sex hormone binding globulin (SHBG) test is used to learn more about your testosterone levels. Testosterone is the male sex hormone. Both men and women have testosterone in their bodies.

You may have this test if you had a different test that showed abnormal testosterone levels, such as a total testosterone test. Sometimes the SHBG test is done at the same time as the total testosterone test.

What is being tested?

SHBG is a protein that is made in the liver. It binds to sex hormones in the blood. A low level of SHBG indicates a low testosterone level. A high level of SHBG indicates a high testosterone level.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.

How do I prepare for this test?

Follow instructions from your health care provider about changing or stopping your regular medicines.

Tell a health care provider about:

• Any allergies you have.
• All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any blood disorders you have.
• Any surgeries you have had.
• Any medical conditions you have.
• Whether you are pregnant or may be pregnant.

How are the results reported?

Your test results will be reported as a value that indicates how much SHBG is in your blood. This will be given as nanomoles of SHBG per liter of blood (nmol/L).

Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:

• Males: 10–57 nmol/L.
• Females: 18–144 nmol/L.

What do the results mean?

A result that is within the reference range is considered normal. This means that there is a normal amount of SHBG and a normal amount of testosterone in your blood.

A result that is higher than the reference range means that there is too much SHBG in your blood. This means that there is too much testosterone in your blood. High SHBG levels may be caused by:

• Liver infection or disease.
• An overactive thyroid gland (hyperthyroidism).
• Hormone replacement therapy, in women.
• Anorexia.
• Taking too much growth hormone.

A result that is lower than the reference range means that there is too little SHBG, and too little testosterone, in your blood. Low SHBG levels may be caused by:

• Polycystic ovarian disease (PCOS), in women.
• Obesity.
• Type 2 diabetes.
• An underactive thyroid gland (hypothyroidism).

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• The sex hormone binding globulin (SHBG) test is done to check your testosterone level. SHBG is a protein that binds to sex hormones in your blood.
• A low level of SHBG indicates that your testosterone level is low. A high level of SHBG indicates a high testosterone level.
• Various health conditions can cause low or high SHBG levels. Talk with your health care provider about what your results mean.