In this article, a new non-invasive diagnostic method, determination of melatonin in effect ‘bystander’, is compared with a routine determination of the basic metabolite of melatonin 6-COMT in the urine. Melatonin is a hormone that plays an important role in the homeostasis of the organism, and it possesses antioxidant and anti-tumour effects. Night insomnia problems lead to a decrease in melatonin production, a phenomenon that is often observed in older people who suffer from this ailment. Somatic pathologies are developed with the passing of the years, and malignant formation incidences are more numerous. Thus, patients of more than 60 years of age with various pathologies have been chosen for the study.

The objective of the study involves comparison of the level of expression of melatonin in the cells of the buccal epithelium with the level of excretion of 6-COMT in the urine of elderly people.