SHBG Blood Test

Sex hormone-binding globulin (SHBG) is a protein that binds to three different sex hormones found in both genders: estrogen, dihydrotestosterone (DHT), and testosterone. A SHBG blood test measures SHBG levels in the blood, and can be used to help diagnose certain hormonal diseases.

Preparation

No special preparation is necessary before an SHBG blood test. You should tell your doctor about any medications — both prescription and over-the-counter — that you’re taking, since they can interfere with test results.

Procedure

An SHBG blood test is a simple and quick procedure. A technician will draw a sample of your blood from a vein in your arm, usually from the inside of your elbow or the back of your hand. This sample will then be taken to a laboratory to be analyzed. Results should be available within a few days.

Types

There are two types of SHBG blood test:

Total SHBG test — Measures SHBG levels in the bloodstream
Free androgen index test — Calculates the percentage of testosterone that’s not bound to SHBG. This test may be recommended for women who have signs of an androgen excess disorder like hirsutism.

Why It’s Performed

A SHBG blood test can help a doctor diagnose or monitor certain conditions. Some of these include:

Hormonal imbalances — Testosterone, estrogen, and other hormones produced by the adrenal glands and ovaries can be affected by SHBG levels.
Polycystic ovary syndrome (PCOS) — This is a common hormonal condition that can lead to problems with infertility.
Hirsutism — This is an increase in body hair in women.
Hypogonadism — This is a condition in which the gonads don’t produce enough hormones, particularly testosterone in males.
Cushing syndrome — This is a condition caused by too much cortisol in the body.

Risks

The risks of an SHBG test are minimal. You may experience occasional discomfort or bruising at the puncture site.

When to Get Tested

Your doctor may recommend an SHBG test as part of a routine physical if they suspect you may have one of the conditions mentioned above. They may also recommend an SHBG test if your testosterone levels are abnormal or if you’re experiencing symptoms such as unexplained weight gain or changes in sexual function.