The Diurnal Cortisol test measures the levels of the key stress hormone, Cortisol, over one daily (ie:Diurnal) cycle. Collection can be done at home or at work. Samples are obtained four times in a day: In the morning (about 30 minutes after waking), noon, mid afternoon, and bedtime. Saliva measurement of Cortisol is easy to do and, unlike blood, where venipuncture may result in an anticipatory rise in Cortisol, with saliva collection it does not.
Cortisol can also be referred to as “the stress hormone.” Repeatedly, or continuously, high salivary Cortisol levels throughout the day may indicate excessive glucocorticoid production, and an inability to adapt to continued stress. Levels are normally at their highest the morning and decline as the day continues. They may fluctuate high or low at any of the four measurement times due to acute or chronic stress. Sustained high or low levels are often found in individuals with an imbalance in adrenal function.
Testing for free cortisol hormone in saliva is a non-invasive, simple way to map out the diurnal cortisol response and a convenient way of assessing adrenal gland function.