Sex Hormone Binding Globulin (SHBG)

Description: Sex Hormone Binding Globulin test is a blood test that is often paired in testosterone testing for men suspected to have low testosterone and women with elevated testosterone.

Also Known As: SHBG Test, TeBG Test, Testosterone-Estrogen Binding Globulin Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Sex Hormone Binding Globulin test ordered?

Sex Hormone Binding Globulin may be ordered by a healthcare provider to investigate infertility, diminished sex drive, and erectile dysfunction in males, or irregular cycles, infertility, and excess body and face hair in women, when total testosterone values do not appear to be consistent with the mentioned signs and symptoms.

What does a Sex Hormone Binding Globulin blood test check for?

SHBG is a liver-produced protein that strongly binds to the hormones testosterone, dihydrotestosterone, and estradiol. SHBG distributes these hormones in the blood as physiologically inactive versions when they are bound. This test examines the amount of SHBG in the blood and is most commonly used to determine whether a person has too much or too little testosterone.

In men, SHBG binds roughly 45 percent to 65 percent of testosterone in the blood, with the rest weakly and reversibly linked to albumin. Only around 2% to 3% of testosterone is accessible to tissues as free testosterone, but testosterone that is weakly linked to albumin is also bioavailable and can be rapidly absorbed by the body's tissues.

In women, a somewhat higher percentage of testosterone is bound to SHBG in the blood than in men. SHBG is important in controlling the quantities of bioavailable male sex hormones and estrogens circulating throughout the body in women. Because SHBG has a stronger affinity for the androgens testosterone and DHT, women with low SHBG may experience signs and symptoms of androgen excess.

A total testosterone test does not differentiate between bound and unbound testosterone; instead, it determines the total amount of testosterone present. In many circumstances, this is sufficient to determine if testosterone production is excessive or inadequate. However, if a person's SHBG level is abnormal, the total testosterone level may not accurately reflect the amount of testosterone available to the person's tissues. When a person's indications and symptoms do not match the results of a total testosterone test, a SHBG test may be conducted.

Lab tests often ordered with a Sex Hormone Binding Globulin test:

Conditions where a Sex Hormone Binding Globulin test is recommended:

How does my health care provider use a Sex Hormone Binding Globulin test?

The sex hormone binding globulin test can be performed to determine whether a man has low testosterone or if a woman has too much testosterone. It can be used in conjunction with other tests to assess a person's sex hormone status.

SHBG is a protein that binds to testosterone, dihydrotestosterone, and estradiol, among other hormones. SHBG distributes these hormones in the blood as physiologically inactive versions when they are bound. Changes in SHBG levels can have an impact on the amount of hormone accessible to the body's tissues.

To assess a person's current hormonal balance, tests for albumin and one or more additional sex hormones, such as prolactin, estradiol, and LH may be conducted.

In men

In order to diagnose the cause of infertility, diminished sex drive, or erectile dysfunction in an adult male, SHBG and total testosterone levels may be ordered. When total testosterone findings are contradictory with clinical symptoms, measuring SHBG in addition to testosterone is extremely beneficial.

Total testosterone in the blood is measured without distinguishing between bound and unbound testosterone; rather, it determines the total amount of testosterone in the blood. In many circumstances, this is sufficient to determine if testosterone production is excessive or inadequate. However, if a person's SHBG level is abnormal, the total testosterone level may not accurately reflect the amount of testosterone available to the body's tissues.

With a simple total testosterone assessment, health practitioners can estimate bioavailable testosterone by measuring SHBG. Because less testosterone is accessible to the body's tissues, increased SHBG in males may be linked to symptoms of low testosterone levels.

Total testosterone should be measured in the initial screening for testosterone deficiency, according to the Endocrine Society's professional standards. If the results are abnormal, the test is repeated the next day. They propose one of the following if repeat readings are low-normal and/or SHBG is abnormal:

In women

The ovaries and adrenal glands produce modest amounts of testosterone in women. Even little increases in testosterone production can throw off the hormone balance, resulting in symptoms including irregular or missed periods, infertility, acne, and excessive face and body hair. These and other signs and symptoms are common in polycystic ovarian syndrome, a disorder marked by an overproduction of male sex hormones. SHBG and testosterone testing may be helpful in detecting and evaluating excess testosterone production and/or decreasing SHBG concentrations, as well as in evaluating women with PCOS.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results