Specialist Diagnostic Services > Diagnostic Tests > Salivary Hormones > Salivary Cortisol

Overview

The measurement of Cortisol has traditionally been done in serum where the hormone is largely bound to carrier proteins and hence inactive. The Synexa Salivary Cortisol test measure the concentration of Cortisol in saliva where it is unbound to carrier protein making it more sensitive and clinically relevant than its serum counterpart.

Cortisol Physiology

Cortisol is a steroid hormone produced by the adrenal gland and is essential for life. Cortisol maintains glucose production from protein, facilitates fat metabolism, supports vascular responsiveness and modulates central nervous function. Cortisol also affects skeletal turnover, muscle function, immune responses and renal functions. The net effect of Cortisol's metabolic effect is catabolic.

A small fraction of Cortisol, about 2-4%, is free and available for exerting an effect on target organs. The remaining Cortisol is bound to the Corticoid Binding Globulin and albumin and exerts no biological effect. Traditionally Cortisol has been determined in serum and measures the total of the free and bound fractions of the hormone. Hence the serum Cortisol concentration is predominantly representing the bound inactive fraction of the hormone.

Salivary Cortisol Test

Synexa measure the concentration of Cortisol in saliva which is unbound to any carrier proteins and is a true reflection of the amount of the hormone that is free and biologically active. Hence salivary Cortisol is significantly more sensitive and clinically useful than serum Cortisol.