SHBG blood test
This test measures the level of sex hormone binding globulin (SHBG) in your blood. SHBG is a protein made by your liver. It binds tightly to three sex hormones found in both men and women. These hormones are estrogen; dihydrotestosterone (DHT), and testosterone. SHBG carries these three hormones throughout your blood.
Although SHBG binds three hormones, the hormone that's critical in this test is testosterone. SHBG controls the amount of testosterone that your body tissues can use. Too little testosterone in men and too much testosterone in women can cause problems. The level of SHBG in your blood changes because of factors such as sex and age. It can also change because of obesity, liver disease, and hyperthyroidism.
You may need this test if your healthcare provider suspects that you have abnormal testosterone levels. The test can help diagnose various conditions and diseases, including:
Androgen deficiency. Low levels of the hormone androgen can cause general weakness and sexual problems in men. In women, androgen may affect thinking and bone strength. It may also prevent the ovaries from working the way they should.
Hypogonadism. This condition happens mostly in men. It is found in men with low testosterone and low sperm production.
Your healthcare provider will likely also order total and free testosterone blood levels. This is because SHBG levels tend to change. Both the SHBG and total testosterone tests are needed to confirm an androgen deficiency.
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
Low levels of SHBG can be related to:
Type 2 diabetes
Acromegaly, or too much growth hormone, causing body tissues grow larger over time
High levels of SHBG can be related to:
Anticonvulsants, or medicine used to treat seizures
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
Pain killers called opiates, medicines for the central nervous system, and recreational drugs can all affect your test results. Having an eating disorder or engaging in excessive, strenuous exercise can also affect your results.
You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.