What is the Origin of Bioavailable Hormone Measurement?

Stemming from analytical biochemistry and endocrinology, the need arose because protein binding affinity varies significantly between hormones like testosterone and estradiol. This distinction separates mere circulation from physiological activity. It represents a refinement over older assays focused only on total mass.

What is the Mechanism of Bioavailable Hormone Measurement?

Measurement protocols typically involve equilibrium dialysis or highly specific immunoassays designed to quantify only the unbound fraction. This unbound fraction directly governs the rate of receptor binding and subsequent genomic or non-genomic signaling events. Higher bioavailable levels correlate directly with expected target tissue response and clinical efficacy.

Bioavailable Hormone Measurement ∞ Area

Bioavailable Hormone Measurement

Meaning

The assessment of the fraction of a circulating hormone that is unbound to carrier proteins, thus capable of interacting with cellular receptors to elicit a biological response. Total hormone concentration often provides an incomplete clinical picture regarding actual tissue effect. Accurate measurement of this free fraction is crucial for diagnosing functional endocrine states.