What is the Origin of Total Serum Testosterone?

This is a standard, fundamental measurement in clinical endocrinology, utilized for decades to assess gonadal function in both men and women. Serum refers to the liquid component of blood after clotting, and testosterone is the principal male androgen. The measurement is the initial step in evaluating symptoms related to hypo- or hyperandrogenism.

What is the Mechanism of Total Serum Testosterone?

Testosterone is synthesized primarily in the testes and ovaries, with a smaller contribution from the adrenal glands, and then released into the circulation. The majority of this circulating hormone binds rapidly to SHBG and albumin, which serve to solubilize the hormone and regulate its delivery to tissues. The total concentration reflects the balance between production, metabolic clearance, and the binding capacity of these transport proteins.

Total Serum Testosterone ∞ Area

Total Serum Testosterone

Meaning

Total serum testosterone is the laboratory measurement of the entire concentration of testosterone present in the blood, encompassing both the biologically active free fraction and the fraction bound to transport proteins like Sex Hormone-Binding Globulin (SHBG) and albumin. This measurement provides a broad assessment of the total androgenic output from the gonads and adrenal glands. While useful as an initial screening tool, it does not fully capture the amount of hormone available to tissues, necessitating consideration of the free fraction for a complete clinical picture.