Measurement of Salivary Cortisol Concentration in the Assessment of Adrenal Function in Critically Ill Subjects: A Surrogate Marker of the Circulating Free Cortisol

Abstract

Salivary cortisol measurements are simple to obtain, easy to measure in most laboratories, and provide an indirect yet reliable and practical assessment of the serum free cortisol concentrations during critical illnesses. The concentrations of the two measures of unbound cortisol determined in two different body fluids correlated very well, regardless of the serum protein concentrations. Measurements of salivary cortisol can serve as a surrogate marker for the free cortisol in the circulation.