SHBG
What it measures, and what changes the number.
Sex hormone binding globulin (SHBG) is a protein made mainly by the liver that binds testosterone, dihydrotestosterone and estradiol in the blood. Hormone bound tightly to SHBG is not readily available to tissues, so the test, usually reported in nmol/L, helps put total hormone levels in context.
It is most often ordered with total testosterone, and the two are used together to calculate free and bioavailable testosterone. It is also read alongside estradiol and other sex hormones.
SHBG is measured by immunoassay, and results can vary somewhat between platforms, which also affects any calculated free testosterone value. Because it is typically drawn with testosterone, the sample is often collected in the morning. Reports may list it as SEX HORMONE BINDING GLOBULIN or SHBG (Globulina fijadora hormonas sexuales).
Reference ranges labs publish
Each lab states an interval for its own method and the population it measured. They differ, they are not interchangeable, and none of them is a verdict on a single result.
- Men, 18 years and over: 13.3 to 89.5 nmol/L · Immunoenzymatic assay · Source: Mayo Clinic Laboratories, SHBG1 (Sex Hormone-Binding Globulin, Serum) (read 2026-09-24)
- Men, 20 to 49 years: 16.5 to 55.9 nmol/L · ECLIA (immunoassay) · Source: Labcorp, 082016 (Sex Hormone-Binding Globulin) (read 2026-09-24)
- Men, 50 years and over: 19.3 to 76.4 nmol/L · ECLIA (immunoassay) · Source: Labcorp, 082016 (Sex Hormone-Binding Globulin) (read 2026-09-24)
- Women, 18 to 46 years: 18.2 to 135.5 nmol/L · Immunoenzymatic assay · Source: Mayo Clinic Laboratories, SHBG1 (Sex Hormone-Binding Globulin, Serum) (read 2026-09-24)
- Women, 47 to 91 years, postmenopausal: 16.8 to 125.2 nmol/L · Immunoenzymatic assay · Source: Mayo Clinic Laboratories, SHBG1 (Sex Hormone-Binding Globulin, Serum) (read 2026-09-24)
- Women, 20 to 49 years: 24.6 to 122 nmol/L · ECLIA (immunoassay) · Source: Labcorp, 082016 (Sex Hormone-Binding Globulin) (read 2026-09-24)
- Women, 50 years and over: 17.3 to 125 nmol/L · ECLIA (immunoassay) · Source: Labcorp, 082016 (Sex Hormone-Binding Globulin) (read 2026-09-24)
Usually reported in nmol/L.
Often read alongside: Total testosterone, Free testosterone (calculated), Bioavailable testosterone, Free testosterone %, Estradiol (E2)
Calculators that use it: Free testosterone calculator, Free androgen index (FAI)