Sex Hormone-Binding Globulin
Test Overview
The SHBG (Sex Hormone-Binding Globulin) Test measures the level of SHBG in the blood, a protein that binds to sex hormones (testosterone, dihydrotestosterone, and estrogen) and regulates their bioavailability in the body. SHBG helps control how much free (active) testosterone and estrogen are available for use by tissues. This test is often used to evaluate hormonal balance, testosterone deficiency, polycystic ovary syndrome (PCOS), and certain metabolic conditions.
Test Uses
- Evaluates testosterone activity by assessing how much is bound versus free.
- Helps diagnose conditions like:
- Hypogonadism (low testosterone in men)
- PCOS (polycystic ovary syndrome in women)
- Estrogen or testosterone imbalances
- Metabolic disorders such as insulin resistance and thyroid dysfunction
- Aids in fertility evaluations and hormonal therapy monitoring
SHBG Test Results & Ranges
| Test Component: | Normal Range: | Abnormal (Possible Conditions): |
|---|---|---|
| SHBG (Men) | 10–57 nmol/L | High: Hyperthyroidism, liver disease, estrogen therapy Low: Obesity, insulin resistance, type 2 diabetes, hypothyroidism, testosterone excess |
| SHBG (Women) | 18–144 nmol/L | High: High estrogen levels, liver disease, hyperthyroidism Low: PCOS, insulin resistance, obesity, high testosterone levels |
| Free Testosterone (Calculated with SHBG) | Varies by age and sex | Helps assess available active testosterone |
- A high SHBG level means less free testosterone is available.
- A low SHBG level means more free testosterone is available, which can contribute to symptoms of testosterone excess (in women) or deficiency (in men).
Expected Turnaround Time
- Results Available: 1–3 business days.
Specimen Requirements
- Sample Type: Blood sample (venipuncture).
- Container: Serum separator tube (SST).
Collection Instructions:
- No fasting required.
- Morning blood draw is preferred for more accurate testosterone measurements.
- Inform your doctor if you are on hormone therapy, birth control pills, or medications affecting liver function, as these can influence SHBG levels.
- Storage: Blood samples should be processed promptly and stored at appropriate temperatures.
Test Details
Clinical Use: Helps diagnose hormonal imbalances in men and women. Used in evaluating testosterone deficiency or excess. Assesses hormonal regulation in metabolic conditions (e.g., insulin resistance, obesity). Aids in evaluating PCOS and fertility concerns.
Limitations: SHBG levels can be affected by age, medications, liver function, and thyroid health. Should be interpreted alongside total and free testosterone levels for a full hormonal assessment.
The SHBG Test is essential for understanding hormone balance, metabolic health, and reproductive function, guiding diagnosis and treatment decisions.