Assessing cortisol and dehydroepiandrosterone (DHEA) in saliva: effects of
collection method
Peter Gallagher*,
Melville M. Leitch,
Anna E. Massey,
R. Hamish McAllister Williams,
Allan H. Young
School of Neurology, Neurobiology and Psychiatry, University of
Newcastle upon Tyne, Newcastle upon Tyne, UK
* To whom correspondence should be addressed.
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Abstract |
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An increasing number of studies are utilizing saliva sampling as a method of
assessing adrenal steroid secretion. Saliva samples have certain advantages over plasma,
being non-invasive and easily collected. However, some methods of collection may
compromise the accuracy of the assay, particularly those which employ aids to stimulate
saliva production. We sought to compare the accuracy of cortisol and
dehydroepiandrosterone (DHEA) measurement by examining the association between plasma
levels, saliva and saliva collected using a citric acid-treated salivette device. Twenty
six healthy male volunteers were recruited for the study. To increase the range of
steroid levels in the samples collected, half the subjects were pre-treated with
hydrocortisone (20 mg, twice a day for 7 days) and half with placebo. Saliva samples
were then collected from each subject using both a 'passive drool' method and a citric
acid-treated salivette. A plasma sample was also collected. Cortisol and DHEA levels
were measured by radioimmunoassay. For cortisol levels, both methods of saliva
collection correlated highly with plasma levels and with each other (r > 0.85;
R2 > 0.72 for all). For DHEA levels, only saliva samples collected
using the unstimulated collection method correlated with plasma levels. DHEA collected
using the salivette device did not correlate significantly with either plasma or the
unstimulated saliva (r < -0.2;R2 < 0.04). It is crucial that
future studies are aware of these issues and are cognizant of the effects of the method
of collection when examining steroid levels in saliva.
Key Words:
cortisol, DHEA, saliva, plasma, salivette, HPA axis
