A computer algorithm to determine the nadir and rise time in nocturnal cortisol secretion

• Published in: Psychoneuroendocrinology Vol. 11; no. 3; p. 359
• Main Authors: Doman, J, Thompson, S, Grochocinski, V, Jarrett, D, Kupfer, D J
• Format: Journal Article
• Language: English
• Published: England 1986
• Subjects: Adolescent; Adrenal Cortex - metabolism; Adult; Aged; Algorithms; Circadian Rhythm; Computers; Depressive Disorder - metabolism; Humans; Hydrocortisone - metabolism; Middle Aged
• ISSN: 0306-4530
• DOI: 10.1016/0306-4530(86)90022-3

The nadir concentration value and the time of the circadian rise are two important characteristics of the nocturnal cortisol secretory pattern. A computer algorithm has been developed which objectively determines these parameters, supplementing the subjective evaluating methods previously used. The algorithm smooths the cortisol values and incorporates the intra-assay variability when calculating the nadir and rise. It was tested on 156 nights of cortisol data for healthy control and depressed subjects. The algorithm results closely matched the nadir and rise time subjectively determined by the investigators. With careful screening of the computer generated results, the algorithm decreases the reliance on subjective methods to determine the actual nocturnal cortisol nadir and rise time.