[Significance and methodology of monitoring calcemia in disorders of mineral metabolism: challenges and prospects]

Disorders of calcium and phosphorus metabolism can cause severe complications that require changing of therapeutic strategies and a long treatment in a hospital. The prevalence of diseases accompanied by calcium metabolism disorders varies from low to moderate. For example, primary hyperparathyroidism, as one of the most common causes of pathological changes in calcium metabolism due to parathyroid hormone hypersecretion, occurs with a frequency of 85 to 233 cases per 100 thousand people. In countries where blood calcium measurements are not routinely carried out, this disease and similar conditions are diagnosed less frequently, and at later stages, with a predominance of manifest and complicated forms. However, calcium metabolism disorders require timely detection and correction in order to prevent complications. At the same time, in a number of clinical situations, standard laboratory analysis is not the optimal diagnostic option due to the duration and complexity of its implementation. In particular, the development of acute hyper- and hypocalcemia requires faster obtaining of blood test results. It is promising to apply technologies allowing to quick assess the current level of calcium directly at a doctor's appointment especially in cases of drug doses adjustment for patients with chronic disorders of calcium metabolism. In this regard, when long-term monitoring of calcemia is required or in emergency situations, the potential benefit can be obtained by using portable Point-of-Care (POC) devices or wearable biosensors. This review examines the clinical and methodological aspects of monitoring calcium levels, their capabilities and practical limitations, and also highlights the prospects for the development and implementation of POC devices and biosensors for ionized calcium.