Abstract

Cortisol is a glucocorticoid hormone with circadian cycle, it shows high levels in the morning and lower in the night. The salivary cortisol is the biologically active fraction and night measurement has been very useful for improving the diagnosis of Cushing’s syndrome, an endocrine disorder characterized by high levels of cortisol and loss of their circadian cycle. A disadvantage of this measurement is the establishment of reference ranges, which depends on the population and technique. Therefore the night salivary cortisol values were determined in a sample of 75 healthy volunteers, aged 18-75 years old. Each volunteer collects two samples in consecutive days and these samples were analyzed by electrochemiluminescence. The average of night salivary cortisol of volunteers was 0.165 ± 0.059 ug/dL with a range from 0.082 to 0.352 ug/dL and no significant differences were found between two samples of cortisol in day 1 and 2. Our results suggest that the proposed cut-off limit 0.32 ug/dL between patients with and without Cushing Syndrome would be suitable for this technique and in our population