If you are reading this, then the chances are that your doctor has ordered an SHBG test.
You are probably wondering what that is and what its results may tell about your health. Perhaps you and your partner are struggling to conceive.
Or maybe you are experiencing unusual acne breakouts and unexplained weight gain.
Whatever the reason may be, we hope that the SHBG test will answer your and your doctor’s questions. Until then, we kindly recommend using this article to get prepared for the test.
What is the SHBG test?
SHBG stands for sex hormone-binding globulin, also known as sex steroid-binding globulin (SSBG). The sex hormone-binding globulin belongs to the group of glycoproteins.
A glycoprotein represents a molecule that consists of, as the name suggests, both a carbohydrate and a protein. SHBG production takes part in the liver. It is thanks to the regulated SHBG secretion that the serum SHBG level is maintained within normal ranges.
But what is the purpose of this globulin? Sex hormone-binding globulin is found in both men and women. Its job is to bind three vital androgen hormones.
Estrogen (also known as estradiol), dihydrotestosterone (DHT), and testosterone are bound to SHBG. As you may know, testosterone is the primary male sex hormone.
DHT is another sex hormone found in males, while estrogen is the primary female sex hormone. These are all examples of what a steroid hormone represents.
There are other steroid hormones found in our body as well. Progesterone and cortisol, for example, are also steroid hormones. These, unlike the three which we mentioned earlier, are not bound to the sex hormone-binding globulin. Instead, these are carried through the body by binding by transcortin. Transcortin is another binding globulin, also known under the name of corticosteroid-binding globulin (CBG).
Once bound to SHBG, the sex hormone is then transported through the blood to each tissue that might need it. It is worth mentioning that the sex hormone-binding globulin has a stronger affinity to serum testosterone and DHT than estrogen. In women, the SHBG aims to maintain the balance between testosterone and estrogen.
Different factors can influence the serum SHBG concentration and cause it to either decline or increase. We will talk more about these factors later. By now, you are probably wondering how is the SHBG level measured.
An SHBG test allows us to measure the SHBG levels in the body. This test is often used to measure the testosterone level or, to be more precise, how much testosterone is being transported to the body’s tissues. You may have heard about a test called total testosterone, which measures bioavailable testosterone levels in the body.
The total testosterone test measures its levels, but it does not measure how much testosterone is being used by the tissues. Unlike the total testosterone, the SHBG test provides this exact information. The results can then reveal whether the body is using too little or too much testosterone, or is using the right amount.
Why do men take this test?
With testosterone being the main male androgen hormone, understandably, this test will most commonly be used among men. Talking about men, the SHBG test often detects androgen deficiency. But it is also done in case the patient shows signs and symptoms of high testosterone levels as well.
It is also used in addition to the total testosterone test to explain the present symptoms. That is because the results of the total testosterone test do not always match the symptoms that the patient is describing. In such a case, further testing needs to be done to determine the cause.
One of the most common reasons why this test is ordered among men is infertility. An SHBG test that shows high SHBG levels may potentially explain the cause of male infertility. It can also explain why the patient is experiencing low libido and erectile dysfunction as well.
While being mainly used in men, the SHBG test is also used among women. For that to be the case, the woman needs to show signs of being overly suggestive to excess male androgen hormones, mainly testosterone.
An SHBG test can reveal the cause of polycystic ovary syndrome (PCOS) and idiopathic hirsutism, among other health issues. PCOS is the usual consequence of having low SHBG levels. In addition to PCOS and low SHBG levels, these patients usually experience insulin resistance and obesity.
The SHBG test is also used to monitor the progress of a sex-steroid and anti-androgen therapy and the diagnosis of any puberty disorders in both men and women. Other than being used to measure the sex hormone level, this test is often used to confirm a condition called thyrotoxicosis.
Thyrotoxicosis is a condition that characterizes itself with excess thyroid hormone. Other possible uses include diagnosing cardiovascular disease, type 2 diabetes, and insulin resistance, especially in women.
Many doctors also use this test to follow the progress of type 2 diabetes and test insulin resistance. This will help them determine if the therapy is providing the desired results.
What do my test results mean?
Before discussing what your results could mean, we first need to explain what the normal SHBG levels are. For adult men, the normal SHBG concentration is between 10 to 57 nmol/L. In women, the levels variate between 18 to 144 nmol/L. children have naturally high SHBG levels.
It is usual for males to experience a rapid decline in their SHBG levels as their testosterone levels are rising. Females, on the other hand, experience a much slower decline in the sex hormone-binding globulin levels.
Having low SHBG levels allows higher levels of free testosterone to be present within the body. On the other hand, elevated SHBG levels result in too little free testosterone being available. This would explain why women have higher SHBG levels than men.
The SHBG levels naturally change over time. Factors such as age, hyperthyroidism, liver disease, obesity, and pregnancy can cause these levels to either increase or decline.
Surprisingly enough, menopause does not seem to cause any significant changes. While there are changes in terms of the estradiol levels, there are no visible changes in the SHBG levels in postmenopausal women.
In men, low SHBG level is linked to symptoms such as:
- Weight gain
- Mood swings
- Increased muscle mass
- Fluid retention
- Erectile dysfunction
- Infertility, etc.
A lot of the time, we see a low SHBG level in men due to their anabolic steroid use. Potential causes of low SHBG levels in men include obesity, hypothyroidism, Cushing syndrome, etc.
Low SHBG levels are also linked to a number of health issues. Science has proven low SHBG levels to be a decisive risk factor for diabetes mellitus. Type 2 diabetes is one of the more severe risks linked to low SHBG.
On the other hand, having elevated SHBG levels, you face hyperthyroidism, hepatitis, and even an increased HIV risk. Anorexia nervosa, which is the most common eating disorder, often causes the SHBG levels to rise. Other potential causes include liver disease, hyperthyroidism, oral contraceptives, hypogonadism, and others.
Does this test pose any risks?
Like any blood test, the SHBG test is considered generally safe. However, some risks may be present. You may experience light bleeding, lightheadedness, infection, and/or bruising. A slight sting or pain may be felt as well the moment the needle pricks the skin. The area may later feel sore. Other than that, the SHBG test is much safer than the majority of invasive tests done on a day-to-day basis.
What might affect my test results?
Surprisingly enough, a long list of factors can influence the current test results. If you are using recreational drugs or any pain killers from the class of opiates, do mention that to your physician. These two factors can significantly alter the blood test results.
Excessive exercise, use of anabolic steroids, and an eating disorder can also affect your test results. Knowing all of this, we ask that you inform your doctor about any of these events in time.
How to prepare
The SHBG test is like any other blood test. It requires a sample of your blood. If you ever have had a blood test done in the past, you are familiar with the basics.
A practitioner will use a needle to collect the blood sample. To do that, they will use a vein in your arm or hand. The blood sample is then sent to the laboratory. The test results will be delivered to your physician, and you can later discuss them together.
Testosterone levels are at their peak in the morning. The reason why we are saying this is because men need to get their SHBG test done in the morning, as early as possible. This will provide the most accurate test results. No fasting is required as you are free to eat your breakfast before you get the test done.
Other than getting informed about what the SHBG test is, there is not much more that you can do to get prepared for it. Be sure to ask your doctor any questions that you may have before the test takes place. I
t is also very important to inform the doctor about any prescription and/or non-prescription medications, including supplements and vitamins, that you are taking at the moment. Biotin supplements, for example, are not to be used 72 hours before the test takes place.
Conclusion
The sex binding-hormone globulin test is one of the most commonly ordered tests. This simple blood test allows the doctor an insight into their patient’s androgen hormone levels. Although slight variations in the SHBG levels and the sex hormone levels take place on a day-to-day basis, too extreme variations cause serious health issues.
In men, this test can potentially provide the answer to what is causing their infertility. The cause of erectile dysfunction, as one of the common sex issues in men, can be revealed as well. This test is ordered in women as well. It usually reveals the cause of excess hair growth but also PCOS.
