What is the Origin of Free Hormone Fractionation?

This analytical technique originated from the limitations of immunoassays that measured total hormone, leading to clinical confusion when binding protein levels were abnormal. Fractionation methods, including equilibrium dialysis or validated calculation models using SHBG and albumin levels, were developed to provide a more physiologically relevant metric. It is a cornerstone of advanced endocrinology.

What is the Mechanism of Free Hormone Fractionation?

The mechanism relies on exploiting the differential binding affinities of hormones to transport proteins like SHBG, often utilizing physical separation techniques or complex binding equilibrium equations. Only the unbound fraction can readily diffuse into target cells to activate nuclear receptors, driving the biological response. Accurate fractionation is essential for diagnosing true hypo- or hyper-function.

Free Hormone Fractionation ∞ Area

Free Hormone Fractionation

Meaning

Free Hormone Fractionation is the analytical process of accurately separating and quantifying the distinct components of a total hormone measurement, specifically distinguishing between bound and unbound fractions in serum. In clinical practice, this is vital for hormones like testosterone and cortisol, where the unbound fraction dictates biological activity at the target tissue. This partitioning reveals the true hormonal environment.