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.

Frequently Asked Questions (FAQs)

What is the SHBG test used for?
The SHBG test measures the level of sex hormone-binding globulin in the blood, which can help assess hormone imbalance and diagnose conditions such as polycystic ovary syndrome (PCOS) or hypogonadism.

What is SHBG?
Sex hormone-binding globulin (SHBG) is a protein that binds to sex hormones, including testosterone and estrogen, in the blood.

How is the SHBG test performed?
The SHBG test involves a blood draw, typically from a vein in the arm, and the sample is then sent to a laboratory for analysis.

What are normal SHBG levels?
Normal SHBG levels vary by age, sex, and laboratory, but generally range from 10-50 nmol/L in adult men and 30-100 nmol/L in adult women.

What can affect SHBG levels?
Several factors can affect SHBG levels, including age, sex, body mass index (BMI), liver function, and certain medications, such as oral contraceptives.

What are the symptoms of low SHBG levels?
Low SHBG levels may be associated with symptoms such as acne, hirsutism, and irregular menstrual cycles in women, and low testosterone levels in men.

What are the symptoms of high SHBG levels?
High SHBG levels may be associated with symptoms such as low libido, erectile dysfunction, and osteoporosis in men, and low estrogen levels in women.

How is the SHBG test interpreted?
The SHBG test results are typically interpreted in conjunction with other hormone level tests, medical history, and physical examination to diagnose and monitor hormone-related conditions.

What are the limitations of the SHBG test?
The SHBG test has limitations, including variability in results between laboratories and potential interference from certain medications or medical conditions.

When is the SHBG test typically ordered?
The SHBG test is typically ordered when a healthcare provider suspects a hormone imbalance or disorder, such as PCOS, hypogonadism, or thyroid dysfunction, and needs to assess sex hormone levels.