Sex Hormone Binding Globulin (SHBG) Serum Test

What is the purpose of this test?

Order the Sex Hormone Binding Globulin (SHBG) Serum Test to measure SHBG levels in the blood to help screen for a testosterone deficiency or excess. Sex Hormone Binding Globulins (SHBG) are proteins produced by the liver that binds to sex hormones, such as dihydrotestosterone (DHT), testosterone, and estradiol (an estrogen). Once attached to the hormones, they transport them through the bloodstream in a metabolically inactive form. By binding to the hormones, SHBG levels are affected by an individual's sex, age, and testosterone or estrogen production. Although SHBG binds to all three sex hormones, this SHBG test is typically used to help evaluate whether a person has an excess or deficiency of testosterone.

In addition, individuals may also order this SHBG Serum Test to help:

• Determine the cause of infertility
• Determine the cause of decreased sex drive and erectile dysfunction

What conditions cause abnormal SHBG levels?

SHBG levels may be affected by other factors besides sex, age, and testosterone or estrogen production. It can also be affected by diseases and conditions such as:

• Liver disease
• Hyperthyroidism
• Diabetes
• Eating disorders (anorexia nervosa)
• Corticosteroids or estrogen use (hormone replacement therapy and oral contraceptives)
• Decreased sex hormone production (hypogonadism)
• Pregnancy
• Obesity
• Autoimmune disorders
• A pituitary gland disorder
• Polycystic ovary syndrome (PCOS)
• Hypothyroidism
• Androgen (steroid) use
• Cushing disease
• Tumor in the testicles or adrenal glands

When should I order a Sex Hormone Binding Globulin Serum Test?

Individuals may order a Sex Hormone Binding Globulin Serum Test if they have experienced symptoms associated with a testosterone excess or deficiency, such as: 

• Loss of sex drive
• Erectile dysfunction or "ED"
• Infertility
• Enlarged breasts
• Lack of face or body hair
• Brittle bones or anemia without a known cause
• Muscle weakness