SHBG Blood Test - More Information

The SHBG test, also known as an SHBG blood test, SHBG lab test and sex hormone-binding globulin test, measures the SHBG blood level.

SHBG plays an important role as a transport protein for androgen and estrogen hormones. SHBG is primarily made in the liver although several other tissues make small quantities. Released into the bloodstream, the primary role of sex hormone-binding globulin is to bind up testosterone and estradiol, preventing these hormones from exerting effects on the end tissues. As a result, abnormally high SHBG levels can result in inadequate amounts of bioavailable testosterone and estradiol, leading to a functional deficiency in these hormones. Some correlations have been found between low SHBG levels and increased cardiovascular risk. Because of this, the SHBG test is often ordered along with the estradiol test and the testosterone total and free test to see how levels of these hormones are affected by SHBG blood levels.

Abnormal SHBG levels often manifest symptomatically in ways related to the estradiol and testosterone that SHBG is responsible for transporting. Specifically, SHBG abnormalities can be correlated with symptoms such as excessive hair growth and sexual abnormalities. The SHBG test is also used in calculating the Free Androgen Index (FAI). The free androgen index is calculated by taking the total testosterone level and dividing it by the SHBG level (total testosterone / SHBG) and, if desired, multiplying it by 100. Healthy men typically have a FAI above 30 while healthy women have an FAI below 10. People interested in getting an advanced look at how testosterone is performing in their bodies should also consider getting the DHEA test. The IGF test is sometimes performed with the SHBG test as high levels of IGF are associated with low SHBG levels.

To get an SHBG test near you at a Quest Diagnostics lab, order online and get your blood drawn at the lab you chose. Once the SHBG lab results are ready, they will be available for download. As can be seen on the sample SHBG lab report above, the SHBG blood levels are reported as a number and can be compared against the reference ranges provided by the lab.