SHBG Blood Test

What is an SHBG blood test?

This test measures the levels of SHBG in your blood. SHBG stands for sex hormone-binding globulin. It’s a protein made by the liver and attaches itself to sex hormones found in both men and women. These hormones are:

Testosterone, the main sex hormone in men
Dihydrotestosterone (DHT), another male sex hormone
Estradiol, a form of estrogen, the main sex hormone in women

SHBG controls how much of these hormones are delivered to the body’s tissues. Although SHBG attaches to all three of these hormones, an SHBG test is mostly used to look at testosterone. SHBG levels can show if there is too much or too little testosterone being used by the body.

Other names: testosterone-estrogen binding globulin, TeBG

What is it used for?

An SHBG test is most often used to find out how much testosterone is going to the body’s tissues. Testosterone levels can be measured in a separate test called total testosterone. This test shows how much testosterone is in the body, but not how much is being used by the body.

Sometimes a total testosterone test is enough to make a diagnosis. But some people have symptoms of too much or too little of the hormone that the total testosterone test results can’t explain. In these cases, an SHBG test may be ordered to provide more information about how much testosterone is available to the body.

Why do I need an SHBG blood test?

You may need this test if you have symptoms of abnormal testosterone levels, especially if a total testosterone test can’t explain your symptoms. For men, it’s mostly ordered if there are symptoms of low testosterone levels. For women, it’s mostly ordered if there are symptoms of high testosterone levels.

Symptoms of low testosterone levels in men include:

Low sex drive
Difficulty getting an erection
Fertility problems

What happens during an SHBG blood test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don’t need any special preparations for an SHBG test.

Are there any risks to the test?

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.

What do the results mean?

If your results show your SHBG levels are too low, it may mean the protein is not attaching itself to enough testosterone. This allows more unattached testosterone to be available in your system. It may cause too much testosterone to go to your body’s tissues.

If your SHBG levels are too high, it may mean the protein is attaching itself to too much testosterone. So less of the hormone is available, and your tissues may be not be getting enough testosterone.

If your SHBG levels are too low, it can be a sign of:

Hypothyroidism, a condition in which your body doesn’t make enough thyroid hormones
Type 2 diabetes
Overuse of steroid medications
Cushing’s syndrome, a condition in which your body makes too much of a hormone called cortisol
For men, it can mean cancer of the testicles or adrenal glands. Adrenal glands are located above the kidneys and help control heart rate, blood pressure, and other bodily functions.
For women, it can mean polycystic ovary syndrome (PCOS). PCOS is a common hormone disorder affecting childbearing women. It is one of the leading causes of female infertility.

Is there anything else I need to know about an SHBG blood test?

SHBG levels are normally high in children of both sexes, so the test is almost always used for adults.

References

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