Sex Hormone-Binding Globulin (SHBG) Test

The Sex Hormone-Binding Globulin (SHBG) test is a blood test used to measure the level of SHBG in the blood. SHBG is a protein produced by the liver that binds to sex hormones, such as testosterone and estrogen, and transports them in the bloodstream.

What is SHBG?

SHBG is a glycoprotein that plays a crucial role in regulating the levels of sex hormones in the body. It binds to sex hormones with high affinity, making them unavailable to bind to their receptors on cells. This helps to regulate the amount of free (active) sex hormones available to the body.

Why is the SHBG test performed?

The SHBG test is performed for several reasons:

• To evaluate conditions related to sex hormone imbalance, such as polycystic ovary syndrome (PCOS), hypogonadism, and hyperandrogenism.
• To monitor the effectiveness of hormone replacement therapy or other treatments that affect sex hormone levels.
• To investigate the cause of infertility or erectile dysfunction in men.
• To assess the risk of certain health conditions, such as cardiovascular disease and osteoporosis, which are associated with low SHBG levels.

How is the test performed?

The SHBG test involves a blood draw, usually from a vein in the arm. The blood sample is then sent to a laboratory for analysis. The test measures the level of SHBG in the blood, which is typically reported in units of nanomoles per liter (nmol/L) or micrograms per milliliter (μg/mL).

Interpretation of results

The normal range for SHBG levels varies depending on factors such as age, sex, and laboratory methods. In general:

• For adult men, a normal SHBG level is typically between 10-50 nmol/L.
• For adult women, a normal SHBG level is typically between 30-100 nmol/L.

Abnormal results may indicate:

• Low SHBG levels: May be associated with conditions such as PCOS, hypogonadism, or insulin resistance.
• High SHBG levels: May be associated with conditions such as hyperthyroidism, liver disease, or certain types of cancer.

Limitations and considerations

The SHBG test has some limitations and considerations:

• SHBG levels can fluctuate throughout the day and may be affected by factors such as diet, exercise, and stress.
• Certain medications, such as oral contraceptives and hormone replacement therapy, can affect SHBG levels.
• The test is not diagnostic on its own and should be interpreted in conjunction with other clinical and laboratory findings.