Long‐term stability of salivary cortisol

Abstract

The measurement of salivary cortisol provides a simple, non-invasive, and stress-free measure frequently used in studies of the hypothalamic-pituitary-adrenal axis activity. In research projects, samples are often required to be stored for longer periods of time either because of the protocol of the project or because of lack of funding for analysis. The aim of the present study was to explore the effects of long-term storage of samples on the amounts of measurable cortisol. Ten pools of saliva were collected on polyester Salivette tampons from five subjects. After centrifugation the samples were either stored in small vials or spiked to polyester Salivette tampons before analysis for cortisol using Spectria RIA kits. The effects of storage were evaluated by a linear regression model (mixed procedure) on a logarithmic scale. No effects on cortisol concentrations were found after storage of saliva at 5 degrees C for up to 3 months or at -20 degrees C and -80 degrees C for up to one year. In contrast, concentrations of cortisol were found to decrease by 9.2% (95% confidence interval (CI): 3.8%; 14.3%) per month in samples stored at room temperature. Repeated freezing and thawing of samples up to four times before analysis did not affect the measured concentrations of cortisol. The coefficient of residual variation (CVresid) for samples stored on Salivette tampons were twice the CVresid for samples stored in separate vials after centrifugation. In conclusion, centrifuged saliva samples for analysis of cortisol may be stored at 5 degrees C for up to 3 months or at -20 degrees C or -80 degrees C for at least one year. However, long-term storage at room temperature cannot be recommended. Repeated cycles of freezing and thawing did not appear to affect the concentrations of cortisol.

Salivary testosterone and cortisol are jointly related to pro-environmental behavior in men

“…Neither testosterone nor cortisol was correlated with the time interval between sampling and freezing (p's > .25). In line with this, previous studies have shown that saliva samples can be mailed and/or stored at room temperature for at least 7 days and sometimes up to 4 weeks without cortisol or testosterone levels being affected (Clements & Parker, 1998;Dabbs, 1991;Garde & Hansen, 2005;Gröschl, Wagner, Rauh, & Dörr, 2001;Jensen et al, 2011;Kirschbaum & Hellhammer, 1989.…”

“…On two subsequent workdays, they collected one saliva sample at home after awakening. Self-sampling of saliva has been described as an adequate method for field studies (Garde & Hansen, 2005;Jensen, Hansen, Abrahamsson, & Nørgaard, 2011). It is widely used since it allows participants to collect samples non-invasively in their natural environment directly after awakening (see e.g., Chida & Steptoe, 2009;Gettler, McDade, & Kuzawa, 2011;Perini, Ditzen, Fischbacher, & Ehlert, 2012).…”

Differentiating between Cushing's disease and pseudo-Cushing's syndrome: comparison of four tests

“…However, an advantage of LNSC measurement is the fact that it is a simple and non-invasive method in the evaluation of patients with suspected hypercortisolism, and it is therefore increasingly used as first-line screening test. Salivary samples can be obtained in ambulatory patients and can be stored at room temperature for several days (35,36,37). A potential concern when saliva sampling is performed at home is contamination with topical or inhaled steroids or collection of insufficient volumes of saliva.…”

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“…Steroid hormones such as C have generally been considered to be stable in saliva even when stored at room temperature for a number of days [23,56]. However, more recent studies have raised concern with respect to sample treatment and storage prior to analysis [61,117,142].…”

“…However, more recent studies have raised concern with respect to sample treatment and storage prior to analysis [61,117,142]. Concentrations of sal-C were found to decrease by 9.2 % per month in samples stored at room temperature [56] compared to baseline. Toone et al [142] observed that following 7 days of storage at 4 °C, sal-T decreased by 26 ± 15 % whereas sal-C remained unchained compared to baseline.…”