Measuring melatonin in humans.

Study Objectives: To provide guidelines for collecting and analyzing urinary, salivary, and plasma melatonin, thereby assisting clinicians and researchers in determining which method of measuring melatonin is most appropriate for their particular needs and facilitating the comparison of data between laboratories.

Methods: A modified RAND process was utilized to derive recommendations for methods of measuring melatonin in humans.

Results: Consensus-based guidelines are presented for collecting and analyzing melatonin for studies that are conducted in the natural living environment, the clinical setting, and in-patient research facilities under controlled conditions.

Conclusions: The benefits and disadvantages of current methods of collecting and analyzing melatonin are summarized. Although a single method of analysis would be the most effective way to compare studies, limitations of current methods preclude this possibility. Given that the best analysis method for use under multiple conditions is not established, it is recommended to include, in any published report, one of the established low threshold measures of dim light melatonin onset to facilitate comparison between studies.