What is Free Testosterone?

Origin: Testosterone is a potent androgenic steroid and major product secreted by the Leydig Cells² of the testis and the adrenal cortex gland in men and from the adrenal cortex and ovaries in women³. It is known as a male sex hormone (androgen).

Feedback Loop: The anterior pituitary gland at the base of the brain controls the amounts of testosterone in the blood in men. When testosterone levels are enhanced, the pituitary gland reduces production. Interestingly, the secretion of testosterone is managed by the negative feedback loop: it requires the participation of luteinizing hormone (LH) and follicle-stimulating hormone (FSH)².

What is the difference between Free Testosterone and Total Testosterone?

Approximately 98% of the testosterone that your body produces is bound to sex hormone binding globulin (60–80%), albumin and cortisol binding globulin⁴. The 2% that is left is known as "free testosterone". It is important to remember that while still under investigation, most researchers accept free testosterone determination as a measure of the biologically active fraction.

Free Testosterone Range (DBC FTE ELISA)

The accuracy of DBC’s Free Testosterone ELISA is supported by a reference interval study, performed according to the Clinical and Laboratory Standards Institute (CLSI) by scientists of the University Health Network (Toronto)⁵.

For example, in this scientific study, serum samples were collected from outpatients for routine physical testing (n=233 females; n=253 males).

• Researchers reported a set of reference intervals for free testosterone analyte in both males and females in the following age cohorts (20–39, 40–59, and ≥60).
• Researchers concluded that the DBC FTE ELISA kit "should be suitable for investigating hyperandrogenism in females".
• This data further supports the diagnostic performance of the DBC ELISA kit as an aid to physicians in diagnosing conditions associated with hyperandrogenism, e.g., hirsutism.

Key Takeaways

Several studies with the DBC Free Testosterone ELISA Kit indicate that:

1. FTE is a marker that could aid physicians in the diagnosis of Insufficient androgen production in males, mainly in middle-aged and elderly males⁶,⁷.
2. The quantitative measurement of FTE with the DBC ELISA kit aids physicians in the diagnosis of conditions associated with hirsutism or hyperandrogenism in females.