Contact Us 1-800-539-6119

Corticosteroid-Binding Globulin (CBG) Blood Test

The CBG Blood Test measures Corticosteroid-binding globulin (CBG, transcortin), the main transport protein for cortisol and corticosterone in vertebrates. This protein binds glucocorticoids with high affinity. In some species, it also binds progesterone and to a lesser extent testosterone. Its specificity varies among species. CBG is important in regulating the actions of glucocorticoids.

Test Code: 500130

CPT Code: 84449

Also Known As: CBG, Corticosteroid-binding Globulin (CBG) Transcortin


Radioimmunoassay (RIA)

Specimen Type: Blood


No special preparation required.

Test Results:

7-10 days. May take longer based on weather, holiday or lab delays.


Corticosteroid-binding globulin (CBG) is the specific high-affinity plasma transport glycoprotein for cortisol. Stress-induced falls in CBG levels may heighten hypothalamic–pituitary–adrenal axis responses and CBG:tissue interactions may allow targeted cortisol delivery. Three genetic variants of CBG have been identified that reduce cortisol binding affinity and/or CBG levels.

Trusted, Secure, & Confidential

Shop All Tests
click here for accessibility toolbar.