- Home
- Tests and Prices
- Test Categories
- Search Tests
- STD Testing
- Blood Tests
- Allergy Testing
- Autoimmune Disease Testing
- Blood Disorder and Blood Disease Testing
- Cancer Detection Testing
- Diabetes Testing
- DNA, Paternity and Genetic Testing
- Drug Screening Testing
- Environmental Testing
- Female-Specific Testing
- Fitness, Nutrition and Anti-Aging Testing
- Gastrointestinal Disease Testing
- General Wellness Testing
- Heart Health and Cholesterol Testing
- Hormone Blood Tests
- Immunization Testing
- Infectious Disease Testing
- Infertility Testing
- Kidney Disease Testing
- Liver Function Tests
- Musculoskeletal Disorders Testing
- Prostate Testing
- Therapeutic Drug Monitoring Testing
- Thyroid Testing
- Find a Lab Location
- All Lab Locations
- Why Online Lab Tests
- How To Order
- About Us
- FAQ
- Health News
- Health Tools
- Health Library
- Health Resources
|
|||||||||
Call 1.877.283.7882 |
Free Androgen Index (FAI) SerumThe free androgen index can be used to estimate physiologically active testosterone. In most men and women, >50% of total circulating testosterone is bound to sex hormone-binding globulin, SHBG, and most of the rest is bound to albumin. SHBG-bound testosterone is not readily available for intracellular complex formation because of SHBG's high binding affinity for testosterone. Thus, testosterone-bound SHBG is considered to be biologically inactive. Albumin has a much lower binding affinity for testosterone but binds a significant portion of the total testosterone because albumin is present at much higher plasma concentrations than SHBG. The rapid dissociation of ”weakly bound” testosterone from albumin, together with a relatively long transit time of albumin through target tissue capillary beds, result in the availability of essentially all albumin-bound testosterone for steroid-receptor interaction. The sum of the free- and albumin-bound testosterone is often referred to as bioavailable testosterone. The concentration of testosterone in the various free and bound forms is essentially a function of total testosterone concentration and the relative concentrations of SHBG and albumin. It can be predicted that increased SHBG will decrease the concentration of both free and bioavailable testosterone for a given total testosterone concentration. The free androgen index can be used to estimate physiologically active testosterone. This index is calculated as the ratio of total testosterone divided by SHBG (both expressed in the same units) and multiplied by 100 to yield numerical results comparable in free testosterone concentration. A significant deviation
from the normal range may require further evaluation by your physician.
The Free Adrogen Index contains the following tests:
|
||||||||
Testosterone, Serum
No Credit Card? Click here for Alternate Payment Methods