Sex hormone-binding globulin (SHBG)
The test determines the level of sex hormone-binding globulin (SHBG) — a specific blood plasma protein binding sex hormones (testosterone and estradiol), regulating their free, biologically active fraction. SHBG plays a key role in maintaining hormonal balance by affecting free testosterone availability in men and women. Used to assess fertility disorder causes, including with normal total testosterone. Applied in hyperandrogenic condition diagnosis in women (PCOS, hirsutism, acne), reduced libido in men, infertility, and erectile dysfunction.
What the test evaluates:
- SHBG concentration in blood serum
- Free-to-bound testosterone and estradiol ratio
- Indirect assessment of sex hormone bioavailability
Biomaterial: Venous blood (serum)
- Draw blood fasting
- Exclude intense physical activity, stress, alcohol, and smoking 24 hours before
- Avoid anabolic steroids and sex hormone-affecting drugs 7 days before
Medications:
- Hormonal contraceptives, hormone replacement therapy, steroid drugs, antidepressants may affect SHBG
- Medication discontinuation only by physician agreement
Recommended for:
- Fertility disorders in women and men
- Reduced libido, erectile dysfunction, infertility in men
- Hyperandrogenism, PCOS, menstrual irregularities, acne
- Hormonal imbalance, obesity, metabolic syndrome
Elevated SHBG: reduces free testosterone level, may cause androgen deficiency symptoms (reduced libido, fatigue, reduced muscle mass)
Reduced SHBG: elevates free testosterone, may manifest as hirsutism, acne, infertility, cycle disorders in women
Note: Combined SHBG and total testosterone determination with free testosterone calculation (Free Androgen Index, FAI) is recommended.
