The antioxidant status of the body is a very important indicator of health. It depends on the ability of body fluids to suppress free radicals. Therefore, the study of methods for analyzing body fluids to determine the total antioxidant capacity (TAC) and total antioxidant activity (CAOA) of the body are very important for medical practice. The composition of urine reflects changes in the body, diet and the content of polyphenol metabolites. At the same time, urine collection is a non-invasive method of analysis, which simplifies the determination of the antioxidant status of the body. The purpose of this work is to describe a non-invasive method for determining the antioxidant status of the body by the total antioxidant activity of urine using potentiometric coulometry on the example of "LitAR," a nanosized composite implantation material, approved for use in medical practice.