Sex hormone-binding globulin
Both men and women need a protein called globulin that binds the sex hormones. Its abbreviation is SHBG (sex hormone-binding globulin, 2737 S-SHBG ). SHBG is created in the liver. The task of SHBG is to carry the sex hormones, namely testosterone and oestradiol, in the bloodstream. When the hormones are bound to SHBG, they are not biologically active. The SHBG level is regulated by the balance between male hormones and female hormones. Male hormones increase the SHBG level and female hormones lower it.
In men, approximately 60% of testosterone and 20% of oestradiol is bound to SHBG in the blood. In women, the corresponding levels are approximately 80% of testosterone and approximately 37% of oestradiol. A considerable share of sex hormones in the blood are loosely bound to another protein, albumin. There are also sex hormones circulating freely in the blood, but their amount is extremely low. Only a small amount of testosterone, approximately 1–3% in men and 0.5–1.3% in women, is free in the blood.
When the SHBG level increases, the total testosterone level (S-Testo) also increases, and correspondingly the level of free blood testosterone (S-Testo-V) decreases. This decreases the libido in men, for example. Correspondingly, when the SHBG level decreases, the total amount of testosterone decreases and the level of free testosterone in the blood increases.
When should SHBG be measured?
SHBG values are often examined if the testosterone result is not compatible with the subject’s symptoms. The reason for testosterone deficiency is examined in men, and the formation of testosterone is investigated in women. In addition, the SHBG level is tested when there is:
- Reduced libido
- decreased hormonal activity of the testicles (andropause)
- erectile dysfunction
- excessive hair growth on the jaw, upper lip, chest, lower abdomen, or back (hirsutism), for example
- disturbance of the menstrual cycle
- polycystic ovary syndrome (PCOS)
What does the SHBG test measure?
The SHBG test provides information about testosterone levels in the blood.
How to interpret the SHBG test result?
Normally, the result is:
Women 15-16v: 10-84 nmol/l Women ≥ 17 v: 20-155 nmol/l
Men 15-18 v: 10-50 nol/l Men ≥ 19 v: 14-71 nmol/l
For men the SHBG level rises along age.
In order to see the comprehensive hormone balance, it is possible to measure testosterone (S-Testo), prolactin (S-PRL), oestradiol (S-E2), and luteinising hormone (S-LH), as well.
Read more about defining reference values.
Please contact your physician or other healthcare professional if you suspect an illness or need help interpreting the results.
What can cause elevated SHBG values?
Elevated SHBG levels are present in connection with pregnancy and oestrogen therapy. In men, the levels increase with age. In addition, high SHBG levels are seen in the following conditions:
- Hyperthyroidism (overactive thyroid)
- Strong weight loss (anorexia nervosa)
- Mental and physical stress or physical exercise
- Certain medicinal products
- Hypogonadism, meaning testosterone deficiency (SHBG increases but free testosterone level decreases)
What can cause decreased SHBG values?
When the SHBG level is decreased, the level of free testosterone (S-Testo-V) is elevated. Decreased SHBG levels are seen in men in connection with male hormone dysfunction. In women, low SHBG levels are caused by polycystic ovary syndrome, obesity, or hyperactive adrenal gland. Low SHBG levels also occur in connection with hypothyroidism.
The most typical additional SHBG tests:
- Oestradiol affects the brain, bones, organs, and reproduction (1366 S-E2)
- Testosterone has physical effects on social and sexual behaviour (2735 S-Testo)
SYNLAB test list: Sex hormone-binding globulin (2737 S-SHBG) https://www.yml.fi/tuotekuvaus_show.php?tuotenro=338
SYNLAB tests: Sex Hormone-Binding Globulin https://www.yml.fi/tuotekuvaus_show.php?tuotenro=338
Fasting is not required
This examination does not require fasting