Salivary Cortisol Determination: Adaptation of a Commercial Serum Cortisol Kit

Abstract

overcome these disadvantages we have modified an existing commercial serum cortisol kit to achieve the sensitivity necessary to enable the direct radioimmunoassay of salivary cortisol at reasonable cost. SUMMARY The determination of cortisol levels in saliva offers a number of significant advantages as compared with plasma or serum measurements, and radioimmunoassay is the technique of choice because of the greater sensitivity required. To date, the assay of salivary cortisol has been limited to only a few centres employing 'in-house' reagents. We describe some simple modifications of a commercial kit, designed for the assay of cortisol in serum and urine, which allow direct and rapid determination of the steroid in saliva. These modifications enable any laboratory with access to a gamma counter to perform large numbers of salivary cortisol assays at relatively low cost.Radioimmunoassays and enzymoimmunoassays have recently been described for the determination of salivary levels of several steroids including cortisol.l " progesterone," 4 17cx-hydroxyprogesterone, 5 testosterone.s ? and dihydrotestosterone." There is increasing evidence that the use of saliva offers many Subjects and sample collection important advantages over plasma or serum samples, especial1y for cortisol assays used to assess the Ten healthy volunteers (seven men and three women) hypothalamic-pituitary-adrenocortical axis.provided paired samples of saliva and blood between From a clinical standpoint, salivary cortisol levels 0800 and 0930 and again between 2200 and 2330. reflect the biologically active 'free' fraction in plasma They then took 0·5 mg of dexamethasone by mouth, and, unlike serum total cortisol determinations, are and further paired samples were collected the next not affected by situations (such as pregnancy) morning. A further five normal subjects had paired associated with changes in circulating cortisol-salivary and blood samples col1ected at 0900 and binding globulin or by drugs (such as salicylates) again 30 and 60 minutes after a single injection of which compete with cortisol for its binding sites. 250 [Jog tetracosactrin (Synacthen). In addition, 150 Use of saliva also avoids the need for venepuncture adult volunteers (62 men and 88 women) aged and, thereby, the risk of stress-stimulating cortisol between 19 and 34, and 105 children aged 4 to 11, secretion," From a practical standpoint, collection of provided morning samples of saliva. Informed saliva is easier and much less expensive than taking a consent was given by al1 the adults and by the blood sample; with minimal instruction, a patient parents of the children in response to a letter from can collect salivary samples at home, thereby greatly their headmaster. facilitating, for example, circadian studies; and Saliva was collected into wide plastic tubes salivary samples greatly facilitate dynamic tests and (Universal containers, 90 x 24 mrn, Sterilin, studies in infants and children.Richmond, Surrey, UK) 15 minutes after rinsing the At present the only disadvantag...

Salivary Cortisol in Psychobiological Research: An Overview

“…Neither max imal stimulation of saliva flow by administration of cit ric acid to the tongue [Walker et al, 1978[Walker et al, , 1984Fergu son et al. 1980;Al-Ansari et al, 1982;Vining et al, 1983a: Vining and McGinley, 1984: Ben-Aryeh et al. 1985: Dirks et al, 1988: Kahn et al, 1988 nor minimal secretion of saliva following medication with anticholin ergic drugs ('dry mouth') [Cook et al.…”

“…1964: Walker et al, 1978;Hiramatsu, 1981: Umeda et al. 1981: Al-Ansari et al. 1982: Riad-Fahmy et al, 1982: Vining et al, 1983b 1984: Hubl et al.…”

“…The proportion of free cortisol in blood has been shown to increase following ACTH injec tion. most probably reflecting the saturated binding ca pacity of CBG under the supraphysiological stimulation of the adrenal gland [Al-Ansari et al, 1982],…”

“…Several workers applied parallel cortisol determina tions in plasma/serum and saliva to study the responses to overnight dexamethasone suppression [Al-Ansari et al, 1982: Poland and Rubin. 1982: Vininget al.…”

Measuring tobacco smoke exposure: quantifying nicotine/cotinine concentration in biological samples by colorimetry, chromatography and immunoassay methods

“…The precipitate obtained is separated at 4 • C by centrifugation (2000 × g) for 10 min [76]. The plasma is frozen at −20 • C until required for analysis.…”