SHBG (Sex Hormone Binding Globulin)
Definition
A protein produced mainly in the liver; it binds to sex hormones such as testosterone and estrogen and regulates their activity levels.
Purpose
Determining how much testosterone is actually free and usable in body tissues.
Why it is needed: The total testosterone test cannot distinguish between the free and bound forms. Testosterone bound to protein cannot be used by tissues; for this reason the total value may look normal while the usable hormone amount is low.
It also helps diagnose hormonal disorders such as polycystic ovary syndrome (PCOS), is used in treatment monitoring, and in investigating early puberty in children.
It may be ordered for symptoms such as low sex drive and erectile difficulty in men, and excess facial and body hair growth with irregular periods in women.
Results
| SHBG | Meaning | Associated conditions |
|---|---|---|
| Low | More testosterone circulates freely | Hypothyroidism, type 2 diabetes, obesity, PCOS in women |
| High | Usable testosterone decreases | Liver disease, hyperthyroidism, certain eating disorders, estrogen-containing medications |
Normal Values
Laboratory specific, refer to the reference range on your report.