[Methodological guidelines for the use of salivary cortisol as biological marker of stress]

AN EASY TO DETERMINE, RELIABLE, MARKER: The measurement of cortisol in saliva provides to the basic scientist as well as to the clinician a reliable tool for investigations of the hypothalamic-pituitary-adrenal axis activity. As with plasma cortisol, the level of cortisol in the saliva is a reliable marker of stress. The major advantage of salivary cortisol is that its sampling technique is non-invasive and can be performed in non-stressful conditions and without laboratory surroundings.

The use of salivary cortisol hence widens the perspectives of interesting research in "out of laboratory" scientific research and clinical research since the samples can be taken at home by the patients themselves.

However, the reliable use of salivary cortisol requires certain methodological prerequisites concerning the sampling technique (collection and storing) and the control of endogenous (individual factors, circadian variations, age, gender, hormonal status, weight) or behavioural (smoking, meals, posture) factors implied in the regulation of saliva. The respect of these prerequisites is essential in order to avoid the potential influence of artefacts during the development of a protocol for clinical research or diagnosis.